DISCONNECTOR

Abstract

 A disconnector for interrupting an electrical circuit comprises a main conductor and a secondary conductor, a conductive blade rotating between a closed-circuit position and an open-circuit position, an insulating casing containing a vacuum ampoule with a fixed electrode and a movable electrode, and a lever system comprising a driven lever and a driving lever for actuating the movable electrode. An auxiliary electrode is provided on the driving lever. The disconnector operates such that, during circuit opening, the conductive blade interacts with the auxiliary electrode, activating the lever system. This movement opens the contact inside the vacuum ampoule, interrupting the current flow.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a disconnector for interrupting electrical circuits in medium and high voltage, in particular of the type that uses a vacuum ampoule for opening and closing an electrical circuit.

BACKGROUND OF THE INVENTION

[0002] Disconnectors for electrical circuits in medium and high voltage are essential devices for the safe and efficient management of the flow of the current. These instruments are designed to interrupt the circuit in emergency situations or for scheduled maintenance, ensuring that operations can be carried out without risk to personnel or damage to equipment.

[0003] As is known, disconnectors rely on metallic contacts that, when closed, allow the current to pass. These contacts are often immersed in insulating gases to prevent electrical arcing and improve operational safety.

[0004] However, over time, the mechanical wear of the contacts and the degradation of the gas may lead to malfunctions, requiring frequent maintenance interventions.

[0005] Furthermore, the process of opening and closing the contacts may become inefficient with prolonged use due to the reduction of contact pressure. This not only increases the risk of failures but may also negatively affect the overall reliability of the system.

[0006] Therefore, there is a growing need in the field to develop advanced solutions that not only improve reliability and service life but are also easy to manufacture and maintain while ensuring high operational efficiency and safety.

[0007] The purpose of the present invention is to propose a disconnector for interrupting electrical circuits in medium and high voltage capable of meeting such a need.

SUMMARY OF THE INVENTION

[0008] This purpose is achieved with a disconnector according to claim 1. The dependent claims describe preferred or advantageous embodiments of the disconnector according to the invention.

[0009] According to an aspect of the invention, there is provided a disconnector for interrupting a circuit in medium or high voltage of an electrical apparatus, comprising a main electrical conductor, a secondary electrical conductor, and a conductive blade extending between a proximal blade end and a distal blade end. The proximal blade end is pivoted to the secondary electrical conductor so as to rotate about a blade axis between a first circuit closing position, in which the distal blade end is in contact with the main electrical conductor, and a second circuit opening position, in which the distal blade end is spaced apart from the main electrical conductor. An ampoule casing is made of insulating material and rigidly connected to the main electrical conductor. A vacuum ampoule is housed in the ampoule casing and contains an ampoule contact formed by a fixed electrode electrically connected to the main electrical conductor and a movable electrode. The movable electrode is translatable with respect to the fixed electrode between a forward contact closing position, in which the movable electrode is in contact with the fixed electrode, and a retracted contact opening position, in which the movable electrode is spaced apart from the fixed electrode. A driven lever is hinged to the ampoule casing so as to oscillate about a driven lever oscillation axis between a driven lever rest position and a driven lever maximum oscillation position, the driven lever being operatively connected to the movable electrode such that its oscillation between the rest position and the maximum oscillation position causes the translation of the movable electrode between the forward and retracted positions. A driving lever is hinged to the ampoule casing so as to oscillate about a driving lever oscillation axis between a driving lever rest position and a driving lever maximum oscillation position in which it drives the driven lever to the driven lever maximum oscillation position. The driving lever supports an auxiliary electrode electrically connected to the movable electrode, the auxiliary electrode facing the distal end of the conductive blade when the conductive blade is in the first circuit closing position. During the rotation from the first circuit closing position to the second circuit opening position, the distal end of the conductive blade comes into contact with the auxiliary electrode, causing the driving lever to oscillate, the driving lever rotating the driven lever to translate the movable electrode from the forward position to the retracted position, and once the second circuit opening position is reached, the distal end of the conductive blade disengages from the auxiliary electrode. This innovative design reduces mechanical wear, ensuring greater durability and reliability.

[0010] In accordance with one embodiment, a distal portion of the driving lever supporting the auxiliary electrode is interposed between the driven lever and the conductive blade when the conductive blade is in the first circuit closing position, such that an oscillation of the driving lever caused by the rotation of the conductive blade results in a simultaneous oscillation of both the driving lever and the driven lever. This improves motion control, reducing the risk of malfunctions.

[0011] In accordance with one embodiment of the invention, the conductive blade and the driving lever are arranged so that, close to the second circuit opening position, the circular trajectory travelled by the distal end of the conductive blade is tangent to the circular trajectory travelled by the auxiliary electrode and, once the point of tangency of said circular trajectories has been passed, the distal end of the conductive blade moves away from the auxiliary electrode. This ensures a precise and controlled disengagement.

[0012] In accordance with one embodiment of the invention, a driven lever spring is associated with the driven lever and is suitable for returning the driven lever to the first position when the conductive blade disengages from the driving lever in the rotation from the first circuit closing position to the second circuit opening position. This ensures an automatic and reliable return to the initial position.

[0013] In accordance with one embodiment of the invention, the distal portion of the driving lever has an insulating region formed on the opposite side with respect to the auxiliary electrode. This increases protection against short circuits.

[0014] In accordance with one embodiment of the invention, said insulating region is at least partially disengaged from the driven lever so that, during the rotation of the conductive blade from the second circuit opening position to the first circuit closing position, the distal end of the conductive blade engages only the insulating region to cause the driving lever to rotate to an end-of-stroke position beyond the rest position, in which the distal end of the conductive blade disengages from the driving lever. This allows precise control of the rotational movement.

[0015] In accordance with one embodiment of the invention, a driving lever spring is associated with the driving lever and is suitable for returning the driving lever to the rest position from the end-of-stroke position. This ensures that the system quickly returns to its initial configuration.

[0016] In accordance with one embodiment of the invention, the auxiliary electrode is connected to the movable electrode by means of a conductor wire. This ensures a reliable and continuous electrical connection.

[0017] In accordance with one embodiment of the invention, the movable electrode is supported by a slider translatable along a slider pin, the driven lever being operatively connected to the slider. This facilitates the precise linear movement of the electrode.

[0018] In accordance with one embodiment of the invention, the rotation axes of the driving lever and the driven lever are parallel and do not coincide with each other. This allows smooth and independent movement of the levers.

[0019] In accordance with one embodiment of the invention, the driving lever and the driven lever are hinged to the ampoule casing so as to be rotatable independently from each other. This allows greater flexibility of movement and control.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The features and advantages of the disconnector according to the invention will in any case become evident from the description provided below of preferred embodiments thereof, given purely by way of example and without limitation, with reference to the accompanying drawings, in which:

• Figure 1 is a side view of the disconnector according to the invention;
• Figures 2 and 2a are two perspective views of the portion of the disconnector comprising the vacuum ampoule and the actuation mechanism of the corresponding electrical contact;
• Figure 3 is a sectional view of the portion of the disconnector of Figures 2 and 2a;
• Figure 3a is an exploded perspective view of the disconnector;

  Figure 4 shows some steps of the movement of the disconnector during the opening of the electrical circuit; and

  Figure 5 shows some steps of the movement of the disconnector during the closing of the electrical circuit.

DETAILED DESCRIPTION OF THE INVENTION

[0021] In the following description, all directional references (for example, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise and counterclockwise) are used solely for identification purposes to assist the reader in understanding the embodiments described and do not impose limitations, particularly with respect to the position, orientation, or use of the embodiments described.

[0022] The coupling references (for example, fixed, coupled, connected and similar terms) are to be interpreted broadly and may include intermediate elements between a connection of components and relative movement between components. Therefore, the coupling references do not necessarily imply that two elements are directly connected and in a fixed relationship with each other.

[0023] With reference to the accompanying drawings, 100 indicates as a whole a disconnector for interrupting a circuit of an electrical apparatus according to the invention.

[0024] In a general embodiment, the disconnector 100 comprises a main electrical conductor 1 and a secondary electrical conductor 2. The main electrical conductor 1 and the secondary electrical conductor 2 are electrically connected to respective poles of an electrical circuit. The disconnector 100 is placed between such poles of the electrical circuit to control the flow of electrical current between said poles. In particular, the disconnector 100 is configured to switch between a rest position, in which it allows the passage of electrical current between the main electrical conductor 1 and the secondary electrical conductor 2, and therefore between the two poles of the electrical circuit, and an active position, in which it interrupts the passage of electrical current between the main electrical conductor 1 and the secondary electrical conductor 2, and therefore between the two poles of the electrical circuit.

[0025] The disconnector 100 comprises a conductive blade 3 extending between a proximal end 3' and a distal end 3".

[0026] The proximal end 3' is pivoted to the secondary electrical conductor 2 so as to rotate about a blade axis (X) between a first circuit closing position and a second circuit opening position.

[0027] In the closing position, the distal end 3" of the conductive blade 3 is in contact with the main electrical conductor 1; in the opening position, the distal end 3" of the conductive blade 3 is spaced apart from the main electrical conductor 1.

[0028] The disconnector 100 comprises a vacuum ampoule 5.

[0029] The vacuum ampoule 5 is housed in an ampoule casing 4 made of electrically insulating material. This ampoule casing 4 is rigidly connected to the main electrical conductor 1. For example, the ampoule casing 4 is screwed to the main electrical conductor 1.

[0030] The vacuum ampoule 5 contains inside it an ampoule contact 50 formed by a fixed electrode 6 and a movable electrode 7. The fixed electrode 6 is electrically connected to the main electrical conductor 1. The movable electrode 7 is translatable with respect to the fixed electrode 6 between a forward contact closing position, in which the movable electrode 7 is in contact with the fixed electrode 6, and a retracted contact opening position, in which the movable electrode 7 is spaced apart from the fixed electrode 6.

[0031] The disconnector 100 comprises a pair of levers, formed by a driven lever 8 and a driving lever 9.

[0032] The driven lever 8 is hinged to the ampoule casing 4 so as to oscillate about a driven lever oscillation axis (Y) between a driven lever rest position and a driven lever maximum oscillation position.

[0033] For example, the driven lever oscillation axis (Y) is parallel to the blade oscillation axis (X).

[0034] The driven lever 8 is operatively connected to the movable electrode 7 such that the oscillation of the driven lever 8 between the rest position and the maximum oscillation position causes the translation of the movable electrode 7 between the forward and retracted positions.

[0035] In one embodiment, the movable electrode 7 is supported by a slider 15 translatable along a slider pin 16. The driven lever 8 is operatively connected to the slider 15. For example, the driven lever 8 comprises at least one plate 8' in which an arcuate lever opening 82 is formed, engaged by a slider pin 84 integral with the slider pin 16. The oscillation of the driven lever 8 causes the translation of the slider pin 84 and therefore of the slider 15. In the embodiment shown in the drawings, the driven lever 8 comprises a pair of plates 8', parallel to each other, extending from opposite sides of the ampoule casing 4.

[0036] The driving lever 9 is also hinged to the ampoule casing 4 so as to oscillate about a driving lever oscillation axis (Z) between a driving lever rest position and a driving lever maximum oscillation position. For example, the driving lever oscillation axis (Z) is parallel to the driven lever oscillation axis (X).

[0037] When the driving lever 9 oscillates from the rest position to the maximum oscillation position, it drives the driven lever 8 into the driven lever maximum oscillation position, thereby causing the translation of the movable electrode 7 from the forward position to the retracted position.

[0038] The driving lever 9 supports an auxiliary electrode 10 electrically connected to the movable electrode 7, for example by means of a conductor wire 14. The auxiliary electrode 10 faces the distal end 3" of the conductive blade 3 when the conductive blade 3 is in the first circuit closing position.

[0039] During the rotation from the closing position to the opening position, the distal end 3" of the conductive blade 3 enters into contact with the auxiliary electrode 10, causing the driving lever 9 to oscillate from the rest position toward the maximum oscillation position. The driving lever 9 drives the driven lever 8 into rotation. Consequently, the movable electrode 7 is translated from the forward position to the retracted position. When the conductive blade 3 reaches the circuit opening position, its distal end 3" disengages from the auxiliary electrode 10, completing the circuit interruption process.

[0040] This design of the disconnector enables a smooth transition between the closed-circuit and open-circuit positions, reducing mechanical wear and improving operational reliability. In particular, the lever system, consisting of a driving lever 9 and a driven lever 8, is designed to coordinate the movement of the movable electrode 7 inside the vacuum ampoule. During circuit opening, the conductive blade 3 contacts the auxiliary electrode 10 supported by the driving lever 9, causing both levers to oscillate and translating the movable electrode 10. This mechanism allows precise and efficient circuit interruption, minimizing the risk of electrical arcing.

[0041] In one embodiment, a distal portion 9' of the driving lever 9, which supports the auxiliary electrode 10, is interposed between the driven lever 8 and the conductive blade 3 when the latter is in the circuit closing position. This arrangement ensures that, during the rotation of the conductive blade 3 from the closing position to the opening position, the oscillation of the driving lever 9 causes the simultaneous oscillation of both the driving lever and the driven lever. The interaction between the driving lever 9 and the driven lever 8, facilitated by their relative arrangement, enables precise control of the translation of the movable electrode 10, reducing the risk of electrical arcing and improving the operational safety of the disconnector.

[0042] In one embodiment, the conductive blade 3 and the driving lever 9 are arranged so that, near the second circuit opening position, the circular trajectory travelled by the distal end 3" of the conductive blade 3 is tangent to the circular trajectory travelled by the auxiliary electrode 10. In this way, a smooth disengagement of the conductive blade 3 from the auxiliary electrode 10 occurs, reducing mechanical stress and component wear.

[0043] Once the point of tangency of said circular trajectories has been passed, the distal end 3" of the conductive blade 3 moves away from the auxiliary electrode 10, thereby ensuring complete circuit opening, with an efficient and safe transition. Such a configuration not only extends the service life of the disconnector but also maintains consistent performance, minimizing the risk of electrical arcing during circuit opening.

[0044] In one embodiment, a driven lever spring 11 is associated with the driven lever 8 and is suitable for automatically returning the driven lever 8 to its initial rest position once the conductive blade 3 disengages from the driving lever 9 during the transition from the circuit closing position to the circuit opening position.

[0045] This automatic reset mechanism ensures that the disconnector is constantly ready for a new operation without requiring manual intervention, thereby improving operational efficiency and reducing downtime.

[0046] The driven lever spring 11 thus ensures that the contact inside the vacuum ampoule closes properly, maintaining system reliability and preventing potential failures due to improper positioning of the lever. This configuration simplifies the maintenance of the disconnector and also extends its operational life.

[0047] For example, the driven lever spring 11 may be made of stainless steel, ensuring corrosion resistance and long operational life, ideal for environments with high humidity or exposure to chemical substances.

[0048] Furthermore, the driven lever spring 11 may be configured as a helical or spiral spring, or as a leaf spring, which can be more compact and suitable for confined spaces. In addition, the spring may be adjustable, allowing the return tension to be modified to suit different operating conditions or force requirements.

[0049] In other embodiments, the driven lever spring 11 may be integrated with a damping system to reduce vibrations and improve the stability of the movement of the driven lever 8. These embodiments allow the disconnector to be adaptable to a wide range of applications and operating environments while maintaining the functionality of returning the driven lever to its initial rest position.

[0050] In one embodiment, the distal portion 9' of the driving lever 9 is provided with an insulating region 12 formed on the side opposite the auxiliary electrode 10. As will be described in more detail below, the insulating region 12 allows the conductive blade 3 to return to the first circuit closing position without coming into contact with the auxiliary electrode 10 and therefore without creating an undesired current path through the electrical contact inside the vacuum ampoule. Therefore, this feature is designed to improve the operational safety of the disconnector, preventing unintentional electrical contacts during operation. The insulating region 12 ensures that the conductive blade 3 interacts exclusively with the intended conductive surfaces, reducing the risk of short circuits or electrical failures. Furthermore, the inclusion of this insulating region 12 helps maintain the integrity of the electrical system, ensuring that the circuit opening and closing operations take place in a controlled and safe manner.

[0051] In some embodiments, the distal portion 9' of the driving lever 9, which includes the insulating region 12, may be made of a plastic material with high thermal and mechanical resistance, such as high-density polyethylene (HDPE), to ensure effective insulation and long operational life.

[0052] In another embodiment, the insulating region 12 may consist of a ceramic or plastic coating applied only to a portion of a metallic structure, for example in the form of a pin, which, for the non-coated portion, acts as the auxiliary electrode 10.

[0053] In addition, the shape of the insulating region 12 may vary: in one implementation, it may have a smooth surface to minimize friction with the conductive blade 3, while in another embodiment it may have a slightly rough surface to improve mechanical stability during interaction with the conductive blade 3.

[0054] The size of the distal portion 9' of the driving lever 9 may be adapted according to the specific requirements of the system, for example by increasing its length to improve mechanical leverage or reducing it to minimize overall dimensions. Finally, the configuration of the insulating region 12 may be such as to include a modular section, which allows the insulating material to be replaced or upgraded without needing to replace the entire driving lever, thereby offering greater flexibility and ease of maintenance.

[0055] In one embodiment, the insulating region 12 of the driving lever 9 is at least partially disengaged from the driven lever 8 such that, during the rotation of the conductive blade 3 from the second circuit opening position to the first circuit closing position, the distal end 3" of the conductive blade 3 engages exclusively with the insulating region 12. In other words, in its return movement toward the main electrical conductor 2, the distal end 3" of the conductive blade 3 intercepts only the driving lever 9 and does not engage the driven lever 8.

[0056] For example, in the embodiment in which the driven lever 8 comprises two plates 8' that are parallel and spaced apart from each other, the insulating region 12 of the distal end 9' of the driving lever 9 extends between the distal ends of the plates 8 of the driven lever 8. In this embodiment, the conductive blade 3 is positioned such that it oscillates in a plane of oscillation extending parallel to and between the two plates 8' of the driven lever 8, for example equidistant from the two plates 8'. Therefore, in the return movement from the second position, the conductive blade 3, passing between the two plates 8' of the driven lever 8, engages only the insulating region 12 extending between the two plates 8', for example orthogonally to them.

[0057] In this return movement of the conductive blade 3, the driving lever 9 is therefore rotated into an end-of-stroke position beyond the rest position (in the opposite direction with respect to the end-of-stroke position that causes the opening of the ampoule contact 50), in which the conductive blade 3 disengages from the driving lever 9 and is thus free to return to the first closed-circuit position, i.e., into contact with the main electrical conductor 1.

[0058] In one embodiment, a driving lever spring 13 is associated with the driving lever 9 and is suitable for returning the driving lever 9 to the rest position from the end-of-stroke position. This reset mechanism ensures that, once the conductive blade 3 has moved the driving lever 9 into an end-of-stroke position beyond the rest position, the driving lever 9 automatically returns to its initial position.

[0059] In the embodiment illustrated in the drawings, the driving lever 9 is U-shaped, or bracket-shaped, comprising the distal portion 9', which extends substantially horizontally and forms or supports the auxiliary electrode 10 and, on the opposite side of said distal portion 9', the insulating region 12, and a pair of lateral flanges 9" extending from the respective ends of the distal portion 9' and hinged to a lower appendix 4' of the ampoule casing 4.

[0060] In this case, a pair of driving lever springs 13 is associated with the driving lever 9, each fixed to a respective end of the lower appendix 4' and acting on a respective lateral flange 9".

[0061] It should be emphasized that, in a preferred embodiment, the rotation axes of the driving lever and the driven lever are parallel and not coincident. This arrangement allows independent movement of each lever, improving the operational flexibility of the disconnector. The separation of the rotation axes enables the levers to operate autonomously, reducing the risk of mechanical interference during operation. This results in more precise control over the circuit interruption process, as each lever can be optimized to perform its specific function without compromising the overall efficiency of the system.

[0062] In particular, the independent hinging of the two levers allows the levers to operate in synergy during the circuit-opening step, while during the closing step, the driving lever can move without influencing the driven lever. This design reduces the risk of mechanical wear and ensures more precise control over the circuit interruption process, resulting in a more robust and reliable mechanism.

[0063] Furthermore, the configuration of the levers enables an automatic return to the rest position, facilitated by the springs associated with the levers, which prepare the disconnector for subsequent operations without requiring manual intervention. This design not only improves the durability of the device but also simplifies its maintenance, offering a safer and more reliable alternative to existing solutions.

[0064] Figure 4 shows the steps of the electrical circuit opening, specifically illustrating how the rotation of the conductive blade 3 induces the oscillation of the driving lever 9, which in turn drives the driven lever 8 into rotation, until a maximum oscillation position is reached in which the electrical contact inside the ampoule is open.

[0065] Figure 4(a) depicts the disconnector 100 in an initial rest position, in which the conductive blade 3, with its distal end 3' in contact with the main electrical conductor 1, allows the flow of electrical current from the main electrical conductor 1 to the secondary electrical conductor 2. From this position, the conductive blade 3 begins to rotate (clockwise in the drawings).

[0066] Figure 4 (b) shows the moment in which the conductive blade 3 has detached from the main electrical conductor 1 and begins to actuate the driving lever 8 by coming into contact with the auxiliary electrode 10. In this initial step of blade rotation, electrical continuity between the main electrical conductor 1 and the secondary electrical conductor 2 is maintained through the ampoule contact 50, which is still closed, the auxiliary electrode 10, connected to the movable electrode 7 of the ampoule contact 5, and the conductive blade 3.

[0067] Figure 4(c) shows the beginning of the rotation of the driving lever 9 and therefore of the driven lever 8, caused by the conductive blade 8. The movable electrode 7 of the ampoule electrical contact 50 begins to retract and separate from the fixed electrode 6. At this stage, the electrical circuit is opened thanks to the opening of the ampoule contact 50, thus avoiding the formation of electrical arcs.

[0068] Figure 4(d) shows the moment in which the circular trajectory of the distal end 3' of the conductive blade 3 is tangent to the circular trajectory of the auxiliary electrode 10 of the driving lever 8. At this moment, the movable electrode 7 has reached the retracted position and the ampoule contact 50 is completely open.

[0069] Figure 4(e) shows the disconnector fully open, with the conductive blade 3 having passed beyond the driving lever 9 and the driven lever 8. The two levers are automatically returned to the rest position thanks to the action of the driven lever spring, which acts on the driven lever 8, which in turn drives the driving lever 9 into the rest position. The rotation of the levers into the rest position causes the movable electrode 7 to return to the forward position, and therefore the ampoule contact 50 to close. The vacuum ampoule 4 is thus ready for a new electrical circuit opening cycle.

[0070] Figure 5 shows the steps of the closing movement of the electrical circuit.

[0071] Figure 5(a) shows the disconnector in the open-circuit position, with the conductive blade 3 in the second open-circuit position and at the beginning of its rotation toward the first closed-circuit position (in the drawings the conductive blade rotates counterclockwise).

[0072] Figure 5(b) shows the disconnector at the moment in which the conductive blade 3 strikes the insulating region 12 of the driving lever 9. As explained above, although the distal portion 9' of the driving lever 9 is located between the driven lever 8 and the main electrical conductor 1, with respect to the trajectory followed by the conductive blade 3 during the closing manoeuvre, the insulating region 12 is not covered by the driven lever 8, and therefore the conductive blade 3 engages the insulating region 12, leaving the driven lever 8 in the rest position.

[0073] Figure 5(c) shows the disconnector at the moment in which the distal end 3" has pushed the driving lever 9 into an end-of-stroke position beyond the rest position, so as to disengage from the driving lever 9 in the final step of the movement back to the first position.

[0074] Figure 5(d) shows the disconnector in the initial rest position, i.e., the closed-circuit position, in which the conductive blade 3 is in contact with the main electrical conductor 1. The driving lever spring has returned the driving lever 9 to the initial rest position.

[0075] To the embodiments of the disconnector according to the invention, a person skilled in the art, in order to meet contingent needs, may introduce modifications, adaptations and substitutions of elements with others functionally equivalent, without departing from the scope of the following claims. Each of the features described as belonging to a possible embodiment may be implemented independently of the other embodiments described.

Claims

1. A disconnector for interrupting a circuit of an electrical apparatus, comprising:

∘ a main electrical conductor (1);

∘ a secondary electrical conductor (2);

∘ a conductive blade (3) extending between a proximal blade end and a distal blade end, where the proximal blade end is pivoted to the secondary electrical conductor (2) so as to rotate about a blade axis between a first circuit closing position, in which the distal blade end is in contact with the main electrical conductor (1), and a second circuit opening position, in which the distal blade end is spaced apart from the main electrical conductor (1);

∘ an ampoule casing (4) made of an insulating material and rigidly connected to the main electrical conductor (1);

∘ a vacuum ampoule (5) housed in the ampoule casing (4) and containing an ampoule contact formed by a fixed electrode (6) electrically connected to the main electrical conductor (1) and a movable electrode (7), the movable electrode (7) being translatable with respect to the fixed electrode (6) between a forward contact closing position, in which the movable electrode (7) is in contact with the fixed electrode (6), and a retracted contact opening position, in which the movable electrode (7) is spaced apart from the fixed electrode (6);

∘ a driven lever (8), the driven lever (8) being hinged to the ampoule casing (4) so as to oscillate about a driven lever oscillation axis between a driven lever rest position and a driven lever maximum oscillation position, the driven lever (8) being operatively connected to the movable electrode (7) so that the oscillation of the driven lever (8) between the rest position and the maximum oscillation position causes the translation of the movable electrode (7) between the forward and retracted positions;

∘ a driving lever (9), the driving lever (9) being hinged to the ampoule casing (4) so as to oscillate about a driving lever oscillation axis between a driving lever rest position and a driving lever maximum oscillation position in which it drives the driven lever (8) to the driven lever maximum oscillation position, the driving lever (9) supporting an auxiliary electrode (10) electrically connected to the movable electrode (7), the auxiliary electrode (10) facing the distal end of the conductive blade (3) when the conductive blade (3) is in the first circuit closing position,

wherein during the rotation from the first circuit closing position towards the second circuit opening position, the distal end of the conductive blade (3) comes into contact with the auxiliary electrode (10) so as to cause the driving lever (9) to oscillate, the driving lever (9) driving the driven lever (8) into rotation so as to translate the movable electrode (7) from the forward position to the retracted position, and wherein, when the distal end of the conductive blade (3) has reached the second circuit opening position, it has disengaged from the auxiliary electrode (10).

2. Disconnector according to claim 1, wherein a distal portion of the driving lever (9) supporting the auxiliary electrode (10) is interposed between the driven lever (8) and the conductive blade (3) when the conductive blade (3) is in the first circuit closing position, so that an oscillation of the driving lever (9) caused by the rotation of the conductive blade (3) causes a simultaneous oscillation of both the driving lever (9) and the driven lever (8).

3. Disconnector according to claim 1 or 2, wherein the conductive blade (3) and the driving lever (9) are arranged so that, close to the second circuit opening position, the circular trajectory travelled by the distal end of the conductive blade (3) is tangent to the circular trajectory travelled by the auxiliary electrode (10), and once the point of tangency of said circular trajectories has been passed, the distal end of the conductive blade (3) moves away from the auxiliary electrode (10).

4. Disconnector according to any one of the preceding claims, wherein the driven lever (8) is associated with a driven lever spring (11) suitable for returning the driven lever (8) to the first position when the conductive blade (3) disengages from the driving lever (9) during the rotation from the first circuit closing position to the second circuit opening position.

5. Disconnector according to any one of the preceding claims, wherein the distal portion of the driving lever (9) has an insulating region (12) formed on the opposite side with respect to the auxiliary electrode (10).

6. Disconnector according to claims 2 and 5, wherein said insulating region (12) is at least partially disengaged from the driven lever (8) so that, during the rotation of the conductive blade (3) from the second circuit opening position to the first circuit closing position, the distal end of the conductive blade (3) only engages the insulating region (12) to cause the driving lever (9) to rotate to an end-of-stroke position beyond the rest position, in which the distal end of the conductive blade (3) disengages from the driving lever (9).

7. Disconnector according to claim 6, wherein the driving lever (9) is associated with a driving lever spring (13) suitable for returning the driving lever (9) to the rest position from the end-of-stroke position.

8. Disconnector according to any one of the preceding claims, wherein the auxiliary electrode (10) is connected to the movable electrode (7) by means of a conductor wire (14).

9. Disconnector according to any one of the preceding claims, wherein the movable electrode (7) is supported by a slider (15) translatable along a slider pin (16), the driven lever (8) being operatively connected to the slider (15).

10. Disconnector according to any one of the preceding claims, wherein the rotation axes of driving lever (9) and driven lever (8) are parallel and do not coincide with each other.

11. Disconnector according to any one of the preceding claims, wherein the driving lever (9) and the driven lever (8) are hinged to the ampoule casing (4) so as to be rotatable independently from each other.

Drawing