Medium voltage switch movable contact assembly

Abstract

A movable contact assembly for a medium voltage switch comprises first and second contact blades facing each other at a certain distance, the first contact blade and the second contact blade being provided with corresponding first and second contact elements, the corresponding first contact elements and the second contact elements being positioned facing each other at the first ends of the corresponding contact blades. The first contact element and the second contact element are adapted to be connected to the corresponding first fixed contacts of the medium voltage switch. The movable contact assembly is characterized in that it comprises at least a spacer disposed between the first contact blade and the second contact blade, wherein the spacer comprises a hollow body for accommodating an elastic element, the elastic element having a first operating end operably connected to one of the first contact blade and the second contact blade and a second operating end operably connected to the other of the first contact blade and the second contact blade, and the elastic element applies a traction force between the first contact blade and the second contact blade.

Description

Technical Field

[0001] The present invention relates to a movable contact assembly for a medium voltage switch and a medium voltage switch unit comprising such a movable contact assembly. More specifically, the present invention relates to a movable contact assembly provided with an improved contact blade system and a medium voltage switch, in particular a disconnector or earthing switch equipped with such an improved contact blade system. Background Art

[0002] For the purposes of the present invention, the term "medium voltage" is intended to mean electrical systems operating at voltage levels above 1 kV AC and 1.5 kV DC up to tens of kV (eg, up to 72 kV AC and 100 kV DC).

[0003] Medium voltage switches, in particular disconnectors and earthing switches, are equipped with a movable contact assembly including a movable contact blade, are well known in the art, and are commonly used, for example, to electrically connect a power terminal to a load terminal, or to ground a load terminal. The movable contact is usually designed to move linearly or rotationally between an open position (in which it is separated from a corresponding fixed contact) and a closed position (in which it is electrically coupled to the fixed contact).

[0004] When the switch is in the closed position, the connection between the movable contact and the corresponding fixed contact should be able to withstand the electromechanical forces generated under both rated current and fault current conditions. For this purpose, a spring system is usually provided to ensure the required contact force between the movable contact and the corresponding fixed contact.

[0005] Attached Figure 1a and Figure 1b An example of a medium voltage disconnector switch of known type is shown.

[0006] The medium voltage disconnector shown in these figures is provided with a movable contact assembly 100, which includes a pair of contact blades 101 and 102 located facing each other at a distance. The first ends of the contact blades 101 and 102 are provided with contact elements for electrical connection with a fixed contact 110.

[0007] exist Figure 1a and 1b In the example shown, the end portions 103 of the contact blades 101 and 102 are rotatably mounted on a fixed support so as to allow the contact blades 101 and 102 to rotate between a closed position shown in the figures and an open position, and vice versa.

[0008] The movement of the movable contact blades 101 and 102 between different operating positions is achieved by a motion system 150 which connects the movable contact blades 101 and 102 to an actuation drive (not shown) via a mechanical transmission system comprising a rod and an operating shaft (partially shown).

[0009] exist Figure 1a and 1b In the disconnector shown, the contact force between the movable contact blades 101 and 102 and the corresponding fixed contact 110 is provided by two compression springs 106 and 107, which are mounted on a pin 105 that laterally connects the movable contact blades 101 and 102 to each other. In this way, due to the pressure applied by the compression springs 106 and 107 to the outer surfaces of the movable contact blades 101 and 102, the required contact force between the movable contact and the fixed contact when in the closed position can be ensured.

[0010] Conventional medium voltage disconnector switches are usually located inside pressurized tanks filled with sulfur hexafluoride (SF6) gas, as this insulating gas ensures excellent performance in terms of dielectric insulation and arc extinguishing capabilities when the current is interrupted. However, it is well known that SF6 is a very potent greenhouse gas and its use is strictly restricted for environmental protection purposes. Therefore, over the years, considerable efforts have been made to design medium voltage switches that do not use SF6 as insulating gas.

[0011] In more recent medium voltage switchgear, SF6 has been replaced by other gases (e.g. pressurized dry air), but these gases have lower insulating properties than SF6. Therefore, the design of medium voltage switchgear should consider the need to keep the electric field under control and avoid the risk of discharge, in addition to other operating requirements.

[0012] The main object of the present invention is to provide a medium voltage switch, in particular a disconnector or an earthing switch, which can overcome or alleviate the disadvantages of the prior art. Summary of the invention

[0013] Within this aim, an object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector / circuit breaker or an earthing switch, which can overcome the problems caused by using insulating gases with lower insulating properties relative to SF6.

[0014] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, wherein discharge problems due to inhomogeneous electric fields are minimized.

[0015] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, wherein the required contact force between the movable contact and the fixed contact in the closed position is ensured.

[0016] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, which is less susceptible to damage than conventional systems.

[0017] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, in which the various components of the switch can be preassembled and pretested as separate kits before final assembly.

[0018] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, which has a simple and compact structure and a relatively small number of components.

[0019] Yet another object of the present invention is to provide a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, which movable contact assembly is relatively simple and inexpensive to manufacture on an industrial level.

[0020] According to the present invention, the above-mentioned aims and objects as well as other objects which will become clear from the following description and the accompanying drawings are achieved by a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, according to the following claim 1 and the related dependent claims.

[0021] In yet another aspect, the invention also relates to a medium voltage switch, in particular a disconnector or earthing switch, comprising a movable contact assembly as described herein.

[0022] In general, the movable contact assembly for a medium voltage switch of the present invention comprises first and second contact blades, which are positioned in parallel and face each other at a distance. The first and second blades are provided with corresponding first and second contact elements, which are positioned facing each other at the first end of the corresponding blades, and the first and second contact elements are adapted to be coupled with the corresponding first fixed contacts of the medium voltage switch.

[0023] The movable contact assembly for a medium voltage switch of the present invention is characterized in that it comprises at least one spacer, which is interposed between the first contact blade and the second contact blade. The spacer comprises a hollow body, which receives an elastic element, which has a first operating end operably connected to one of the first and second contact blades and a second operating end operably connected to the other of the first and second contact blades, and the elastic element applies a traction force between the first and second contact blades.

[0024] For the purpose of the present invention, the terms "first operating end" and "second operating end" are not intended to refer to the physical limit points of the elastic element, but rather to the operating points of the elastic element that perform a designated function.

[0025] In practice, as better explained below, in the movable contact assembly for a medium voltage switch of the present invention, the design and positioning of the elastic element provides an effective system for providing the required contact force between the movable contact and the fixed contact in the closed position without the trouble caused by uneven electric fields.

[0026] In fact, in Figure 1a and Figure 1b In the conventional system shown, the projections formed on the outer surfaces of the movable contact blades 101 and 102 by the transverse pins 105 and the springs 106 and 107 mounted on the pins 105 can generate a strong electric field, which may cause discharge.

[0027] In contrast, in the movable contact assembly currently claimed for protection, the elastic element - for example, a spring - and the corresponding housing arranged in the hollow body of the spacer are located in the defined space between the contact blades, and there are no obvious protrusions on the outer surfaces of the contact blades that would produce uneven electric fields with discharge-related problems.

[0028] Furthermore, if arcing occurs in the area of ​​the contact blades during normal switching operation or in the event of a fault current, the potential risk of damaging the elastic element can be avoided because the elastic element is protected within the hollow body of the spacer.

[0029] It should also be noted that the subassembly comprising the spacer with the hollow body and the elastic element can be manufactured as a separate kit, which is preassembled and adjusted to provide the required force value. Therefore, the production process of the entire movable contact assembly is more efficient and simplified.

[0030] According to some embodiments of the movable contact assembly of the present invention, the spacer is preferably positioned close to the first and second contact elements. In this way, the force exerted by the elastic element on the contact system in the closed position can be maximized.

[0031] Preferably, the elastic element is positioned substantially perpendicular to the first and second contact blades. In practice, in this embodiment, the movable contact blades are positioned substantially parallel to each other and at a distance, while the elastic element is positioned transversely between the contact blades and substantially perpendicular to the contact blades.

[0032] In an overall embodiment of the present invention, the operative connection of the elastic element to the blade can be direct, i.e. the first and second operative ends of the elastic element can be directly connected to the contact blade. However, as better explained in the following detailed description, this operative connection between the elastic element and the blade can involve an intermediate element.

[0033] According to the invention, in a very preferred embodiment of the movable contact assembly, the spacer advantageously comprises a coupling element slidably inserted into the hollow body. A first end of the coupling element is rigidly coupled to one of the first or second contact blades, while the hollow body is rigidly coupled to the other of the first or second contact blades. For the purposes of the present invention, the term "first end of the coupling element" is not intended to refer to the physical limit point of the coupling element, but rather to an operating point for performing a specified function.

[0034] In practice, according to this embodiment, the spacer subassembly comprises two elements, namely the hollow body and the coupling element, each of which is rigidly connected relative to the other to a different contact blade.

[0035] Thus, according to a preferred way of implementing this embodiment, the first operating end of the elastic element can be operably connected to one of the connecting element or the hollow body, and the second operating end of the elastic element can be operably connected to the other of the connecting element or the hollow body.

[0036] In this way, as better explained below, the resilient element is operatively connected to the first and second movable contact blades through the hollow body of the spacer and through the coupling element.

[0037] According to the invention, in a possible practical embodiment of the movable contact assembly, the coupling element may advantageously comprise a pin having a first end and a second end, the first end being rigidly coupled to one of the first or second contact blades and the second end being operably connected to the elastic element.

[0038] For the purposes of the present invention, the term "pin" is intended to refer generally to a shaped body that is rigidly coupled to one of the contact blades at one end and operatively connected to a resilient element at the other end. Furthermore, the terms "first end" and "second end" of the pin are not intended to refer to the physical extreme points of the pin, but rather to the operating points that perform a specified function.

[0039] In particular, in a possible embodiment of the present invention, the second end of the pin may include a first protruding surface positioned inside the hollow body.

[0040] Then, according to a preferred way of implementing this embodiment, the first protruding surface on the second end of the pin may be operatively connected to one of the first or second operative ends of the elastic element.

[0041] In this arrangement, according to some embodiments of the invention described in more detail below, the hollow body of the spacer may include a second protruding surface operably connected to the other of the first or second operative ends of the resilient element.

[0042] As better explained in the detailed description of the invention below, the first and second protruding surfaces may be made integrally on the body and hollow body of the corresponding pin or may be made of elements fixed to the body and hollow body of the corresponding pin.

[0043] In practice, according to this embodiment, the elastic element is operatively connected to one of the contact blades by an operative connection with the coupling element and to the other contact blade by an operative connection with the hollow body of the spacer.

[0044] According to some embodiments of the present invention, the elastic element may be a compression spring disposed between a first protruding surface on the second end of the pin and a second protruding surface on the hollow body of the spacer. In particular, the compression spring may have a first operating end resting on the first protruding surface and a second operating end resting on the second protruding surface, thereby pushing the first and second protruding surfaces and thus the corresponding pin and hollow body in opposite divergent directions / directions away from each other. In other words, in this embodiment, the pin and the hollow body of the spacer are subjected to a force tending to push them apart from each other.

[0045] According to some alternative embodiments of the present invention, the elastic element may be a traction spring interposed between a first protruding surface on the second end of the pin and a second protruding surface on the hollow body of the spacer. In particular, the traction spring may have a first operating end engaged with the first protruding surface and a second operating end engaged with the second protruding surface, thereby pulling the first and second protruding surfaces in opposite converging directions / directions toward each other, thereby pulling the corresponding pin and hollow body. In practice, in this embodiment, the pin and the hollow body of the spacer are subjected to a force tending to pull them toward each other.

[0046] According to some embodiments of the movable contact assembly of the present invention, the movable contact assembly may advantageously comprise an adjustment device for adjusting the preload of the elastic element, such as a washer, a shim or a threaded device for adjusting the preload of the elastic element.

[0047] In some embodiments of the movable contact assembly of the present invention, depending on the intended application, the first and second blades may be provided with corresponding third and fourth contact elements, which are suitable for coupling with the corresponding second fixed contact of the medium voltage switch and are positioned facing each other at the second end of the corresponding blade. Advantageously, in these embodiments, the movable contact assembly may also include a first spacer and a second spacer of the spacers as described above, the first spacer and the second spacer being positioned at positions close to the first and second contact elements and the third and fourth contact elements, respectively. In other words, when a double contact system is involved, a double spacer system and corresponding elastic elements may be provided. These spacers are advantageously positioned at positions close to the contact points so that the force generated by the elastic element on the contact system in the closed position can be maximized.

[0048] A Medium Voltage switchgear unit comprising a movable contact assembly as described herein is also part of the invention.

[0049] In particular, the medium voltage switch of the present invention may be a disconnector or a grounding switch, or may be a combination of a disconnector and a grounding switch.

[0050] In the medium voltage switchgear unit of the present invention, the arrangement and the type of movement (e.g. linear or rotary) of the movable contact assembly can be arbitrarily selected according to the needs and solutions well known in the art. In addition, the medium voltage switchgear unit is usually provided with a kinematic chain and a transmission rod between the movable contact assembly and the actuator, which can be of a type arbitrarily selected according to the needs and solutions well known in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Further features and advantages of the present invention will become more apparent from the description of a preferred but non-exclusive embodiment of the invention shown by way of example in the accompanying drawings, in which:

[0052] - Figure 1a is a first view of an embodiment of a contact assembly of a medium voltage disconnector in the prior art;

[0053] - Figure 1b is a second view of an embodiment of a contact assembly of a medium voltage disconnector in the prior art;

[0054] - Figure 2a is a first view of a first embodiment of a contact assembly comprising a movable contact assembly for a medium voltage switch according to the present invention;

[0055] - Figure 2b is a second view of a first embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0056] - Figure 2c is a cross-sectional view of a detail of a first embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0057] - Figure 3a is a side view of components of a first embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0058] - Figure 3b is a first cross-sectional view of components of a first embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0059] - Figure 3c is a second cross-sectional view of components of a first embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0060] - Figure 4a is a first view of a second embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0061] - Figure 4b is a second view of a second embodiment of a contact assembly according to the invention comprising a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch;

[0062] - Figure 5a yes Figure 4a-4b A side view of a movable contact assembly of a medium voltage switch, in particular a disconnector or earthing switch, used in an embodiment of the invention;

[0063] - Figure 5b yes Figure 4a-4b A first cross-sectional view of a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, used in an embodiment of the present invention;

[0064] - Figure 5c yes Figure 4a-4b A second cross-sectional view of a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, used in an embodiment of the present invention;

[0065] - Figure 6a is a side view of a third embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or an earthing switch, according to the present invention;

[0066] - Figure 6b is a first sectional view of a third embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or an earthing switch, according to the present invention;

[0067] - Figure 6c is a second cross-sectional view of a third embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or an earthing switch, according to the present invention;

[0068] - Figure 7a is a first cross-sectional view of a component of a third embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or an earthing switch, according to the present invention;

[0069] - Figure 7b is a second cross-sectional view of a component of a third embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or an earthing switch, according to the present invention;

[0070] - Figure 8a is a first cross-sectional view of components of a first embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, according to the present invention;

[0071] - Figure 8b is a second cross-sectional view of components of a first embodiment of a movable contact assembly for a medium voltage switch, in particular a disconnector or earthing switch, according to the invention. DETAILED DESCRIPTION

[0072] With reference to the accompanying drawings, the present invention more generally relates to a movable contact assembly for a medium voltage switch, in the embodiment of the accompanying drawings, the medium voltage switch is a disconnector, and the movable contact assembly is a rotary type. As mentioned above, the arrangement and the type of movement of the movable contact assembly (e.g., linear or rotary) can be arbitrarily selected according to needs and solutions well known in the art. In addition, the medium voltage switch unit is usually provided with a kinematic chain and a transmission rod between the movable contact assemblies, as well as an actuator that can be arbitrarily selected according to needs and solutions well known in the art, which will not be repeated here.

[0073] The movable contact assembly of the present invention (indicated by reference numerals 1, 10, 50 in the various embodiments) generally comprises a first contact blade 61 and a second contact blade 62, which are positioned facing each other in parallel and at a distance.

[0074] refer to Figure 2a and 2b The first contact blade 61 and the second contact blade 62 are respectively provided with corresponding first contact elements 71 and second contact elements 72 which are positioned facing each other at first ends 610, 620 of the inner surfaces of the corresponding blades 61, 62.

[0075] For purposes of the present invention, the term "inner" referring to contact blades is intended to refer to surfaces of the blades in the assembly that face each other, and the term "outer" referring to contact blades is intended to refer to surfaces of the blades in the assembly that point outwardly.

[0076] exist Figure 2a and 2b In the illustrated embodiment, the end portions 103 of the contact blades 61 and 62 are rotatably mounted on a fixed support, thereby allowing the contact blades 61 and 62 to rotate between a closed position shown in the figure (in which the first contact element 71 and the second contact element 72 are electrically connected to the first fixed contact 110 of the medium voltage switch) and an open position, and vice versa.

[0077] The movement of the movable contact blades 61 and 62 between the different operating positions is imparted by a movement system 150 which connects the movable contact blades 61 and 62 to an actuation drive (not shown) via a mechanical transmission system comprising a rod and an operating shaft (partially shown).

[0078] In the various embodiments shown in the drawings, the movable contact assembly 1 , 10 , 50 of the present invention includes at least one spacer 20 , 200 interposed between the inner surfaces of the first contact blade 61 and the second contact blade 62 .

[0079] In general, the spacer 20, 200 includes a hollow body 21, 210 that receives a resilient element 30, 300. The resilient element 30, 300 has a first operating end 31, 310 operably connected to one of the first contact blade 61 and the second contact blade 62 and a second operating end 32, 320 operably connected to the other of the first contact blade 61 and the second contact blade 62.

[0080] For example, the hollow body 21 , 210 may be cylindrical, wherein one base of the cylinder is closed and rests on one of the contact blades 61 or 62 , and the other base of the cylinder is open and points toward the other contact blade 62 or 61 .

[0081] The positioning and features of the resilient element 30, 300 are such that it applies a traction force between the first contact blade 61 and the second contact blade 62, thereby providing the required contact force between the fixed contact element 110 and the movable contact elements 71, 72 when they are in the closed position.

[0082] In a general embodiment of the present invention, the operable connection of the elastic element 30, 300 with the contact blade 61, 62 may be direct, i.e. the first operating end 31, 310 and the second operating end 32, 320 of the elastic element 30, 300 may be directly connected to the contact blade 61, 62. However, the operable connection between the elastic element 30, 300 and the contact blade 61, 62 advantageously involves an intermediate element, as better explained in the following description of the embodiment shown in the figures.

[0083] In the embodiments of the movable contact assembly 1, 10, 50 shown in the drawings, the spacer 20, 200 and the elastic element 30, 300 are advantageously positioned close to the first contact element 71 and the second contact element 72, so as to maximize the force exerted by the elastic element 30, 300 on the contact system in the closed position.

[0084] Furthermore, the spacers 20 , 200 and the elastic elements 30 , 300 are advantageously positioned such that the force exerted by the elastic elements 30 , 300 on the contact blades 61 , 62 is substantially perpendicular to the inner surfaces of the first and second contact blades 61 , 62 .

[0085] As shown in the accompanying drawings, in particular Figure 3a-3c As shown in FIGS. 7 a - 7 b and 8 a - 8 b , the spacer 20 , 200 includes a coupling element 40 , 400 that is slidably inserted into the hollow body 21 , 210 of the spacer 20 , 200 .

[0086] The coupling element 40, 400 has a first end 41, 410, which is rigidly coupled to one of the first contact blade 61 or the second contact blade 62 (e.g., the contact blade 62 in the drawings). The rigid coupling can be achieved, for example, by a threaded device 92 fixed to a threaded portion of the first end 41, 410 of the coupling element 40, 400. However, other fixing means can also be used, such as a snap-fit ​​means, screwing directly on the contact blade, a fastening means and the like.

[0087] Then, the hollow body 21 , 210 is rigidly coupled with the other of the first contact blade 61 or the second contact blade 62 (eg, the contact blade 61 in the drawings).

[0088] For example, in the embodiment shown in the figures, the hollow body 21, 210 may be cylindrical, one base of which is closed and rests on the inner surface of the contact blade 61. The fixing pin 28, 280 protrudes from this base and is inserted into a seat on the contact blade 61. The rigid connection between the hollow body 21, 210 and the contact blade 61 may be obtained, for example, by a threaded device 91, which is fixed on the threaded portion of the fixing pin 28, 280 protruding from the base of the hollow body 21, 210. However, other fixing means may be used, such as a snap-on means, screwing directly on the contact blade, a fastening means and the like.

[0089] Special References Figure 3a-3c , 7a-7b and 8a-8b, which show the detailed design of possible embodiments of the spacer 20, 200, the first operating end 31, 310 of the elastic element 30, 300 is operably connected to the connecting element 40, 400 or one of the hollow bodies 21, 210, and the second operating end 32, 320 of the elastic element 30, 300 is operably connected to the connecting element 40, 400 or the other of the hollow bodies 21, 210.

[0090] In the embodiments shown in the above figures, the first operating end 31 , 310 of the elastic element 30 , 300 is operably connected to the coupling element 40 , 400 , and the second operating end 32 , 320 of the elastic element 30 , 300 is operably connected to the hollow body 21 , 210 .

[0091] In the embodiment of the figures, the coupling element 40, 400 comprises a pin 45, 450, the pin 45, 450 having a first end 41, 410 and a second end 42, 420, the first end 41, 410 being rigidly coupled to one of the first contact blade 61 or the second contact blade 62, and the second end 42, 420 being operatively connected to the elastic element 30, 300. In the embodiment shown in the above figures, the first end 41, 410 of the pin 45, 450 is rigidly coupled to the second contact blade 62, and the second end 42, 420 of the pin 45, 450 is operatively connected to the elastic element 30, 300.

[0092] The shape and size of the pins 45, 450 may vary depending on the design and functional characteristics of the spacer assembly 20, 200, as shown in some examples reported below.

[0093] For example, the second end 42, 420 of the pin 45, 450 may include a first protruding surface 46, 460 located inside the hollow body 21, 210. In addition, in this case, the shape and size of the first protruding surface 46, 460 may be different according to the design and functional characteristics of the spacer assembly 20, 200. For example, the first protruding surface 46, 460 may be integrally formed on the body of the corresponding pin 45, 450, or may be formed by an element fixed to the body of the pin 45, 450.

[0094] In general, the first protruding surface 46, 460 on the second end 42, 420 of the pin 45, 450 is operatively connected to one of the first operating end 31, 310 or the second operating end 32, 320 of the elastic element 30, 300. Figure 3a-3c , 7a - 7b and 8a - 8b , the first protruding surface 46 , 460 on the second end 42 , 420 of the pin 45 , 450 is operably connected to the first operating end 31 , 310 of the elastic element 30 , 300 .

[0095] Then, the hollow body 21, 210 may include a second protruding surface 26, 260, which is operatively connected to the other of the first operating end 31, 310 or the second operating end 32, 320 of the elastic element 30, 300. Figure 3a-3c , 7a - 7b and 8a - 8b , the second protruding surface 26 , 260 of the hollow body 21 , 210 is operably connected to the second operating end 32 , 320 of the elastic element 30 , 300 .

[0096] The shape and size of the second protruding surface 26, 260 may vary according to the design and functional features of the spacer assembly 20, 200. For example, the second protruding surface 26, 260 may be integrally formed on the body of the corresponding hollow body 21, 210, or may be formed by an element fixed to the hollow body 21, 210.

[0097] For example, refer to Figure 2a-2c , 3a-3c, 4a-4b, 5a-5c, 8a-8b, the hollow body 21 is cylindrical, one base of which is closed and rests on the inner surface of the contact blade 61. The fixing pin 28 protrudes from this base and is inserted into a seat on the contact blade 61. The rigid connection between the hollow body 21 and the contact blade 61 is obtained by a threaded device 91, which is fixed on the threaded portion of the fixing pin 28 protruding from the base of the hollow body 21.

[0098] On the opposite side of the hollow body 21 relative to the fixing pin 28, the hollow body 21 is provided with a second protruding surface 26 positioned on the inner surface of the hollow body 21. The second protruding surface 26 may be made integrally with the hollow body 21, or, as shown in the illustrated embodiment, may be made of a separate element, such as a retaining ring inserted into a groove formed on the inner surface of the hollow body 21.

[0099] Then, in Figure 2a-2c In the embodiments of , 3a-3c, 4a-4b, 5a-5c, 8a-8b, the coupling element 40 comprises a profiled pin 45 having a first end 41 inserted in a seat on the contact blade 62. The rigid coupling between the pin 45 and the contact blade 62 is obtained by means of a threaded device 92 fixed to a threaded portion of the first end 41 of the pin 45.

[0100] The pin 45 is provided with a first protruding surface 46 on the second end 42 of its body, which is a flat surface extending transversely from the longitudinal extension of the shaped body of the pin 45. In this case, the pin 45 is inserted into the cylindrical hollow body 21 so that the first protruding surface 46 is located at a position corresponding to the closed base of the cylindrical hollow body 21.

[0101] exist Figure 2a-2c In the embodiments of 3a-3c, 4a-4b, 5a-5c, and 8a-8b, the elastic element 30 is a compression spring, which is housed inside the hollow body 21 and disposed between the first protruding surface 46 on the pin 45 and the second protruding surface 26 on the hollow body 21.

[0102] In particular, the compression spring 30 has a first operating end 31 acting on the first protruding surface 46 (and thus on the pin 45) and a second operating end 32 acting on the second protruding surface 26 (and thus on the hollow body 21), so that the first protruding surface 46 and the second protruding surface 26 are urged in opposite divergent directions. As a result, the pin 45 and the hollow body 21 are also urged in opposite divergent directions.

[0103] In practice, reference Figure 5a-5c 8a-8b, the hollow body 21 is subjected to a force directed to the left side of the drawing, while the pin 45 is subjected to a force directed to the right side of the drawing. Therefore, the first contact blade 61 rigidly coupled to the hollow body 21 is also subjected to a force directed to the left side of the drawing, while the second contact blade 62 rigidly coupled to the pin 45 is also subjected to a force directed to the right side of the drawing. Due to this combination of forces, a traction force is obtained between the first contact blade 61 and the second contact blade 62 in general.

[0104] exist Figure 6a-6cIn the embodiment of 7a-7b, the hollow body 210 is cylindrical, one base of which is closed and rests on the inner surface of the contact blade 61. A fixing pin 280 protrudes from the base and is inserted into a seat on the contact blade 61. The rigid connection between the hollow body 210 and the contact blade 61 is obtained by means of a threaded device 91, which is fixed on the threaded portion of the fixing pin 280 protruding from the base of the hollow body 210.

[0105] On the same side of the hollow body 210 relative to the fixing pin 280, the hollow body 210 is provided with a second protruding surface 260 positioned on the inner surface of the hollow body 210. In particular, as shown in the illustrated embodiment, the second protruding surface 260 is integrally formed on the inner surface of the closed base of the cylinder of the hollow body 210. Alternatively, it may be made of a separate element, such as a hook or similar fixing device, which is positioned on the inner surface of the closed base of the cylinder of the hollow body 210.

[0106] Then, in Figure 6a-6c In the embodiment of 7a-7b, the coupling element 400 comprises a shaped pin 450 having a first end 410 which is inserted into a seat on the contact blade 62. The rigid coupling between the pin 450 and the contact blade 62 is obtained by means of a threaded device 92 which is fixed on a threaded portion of the first end 410 of the pin 450.

[0107] The pin 450 is provided with a first protruding surface 460 on the second end 420 of its body, which is a surface provided with fixing means, such as a hole for inserting the hooking end of the spring, which extends longitudinally along the extension direction of the shaped body of the pin 450.

[0108] In this case, the pin 450 is inserted into the cylindrical hollow body 210 so that the first protruding surface 460 is positioned corresponding to the open base of the cylindrical hollow body 210. As shown in the drawings, the second end 420 of the pin 450 can be shaped to provide an abutment surface that cooperates with the inner surface of the hollow body 210, thereby giving the system more stability.

[0109] exist Figure 6a-6c In the embodiments of FIGS. 7 a - 7 b , the elastic element 300 is a traction spring received inside the hollow body 210 and interposed between the first protruding surface 460 on the pin 450 and the second protruding surface 260 on the hollow body 210 .

[0110] In particular, the traction spring 300 has a first operating end 310 acting on the first protruding surface 460 (and thus on the pin 450), and a second operating end 320 acting on the second protruding surface 260 (and thus on the hollow body 210), so that the first protruding surface 460 and the second protruding surface 260 are pulled in opposite converging directions. As a result, the pin 450 and the hollow body 210 are also pulled in opposite converging directions.

[0111] In practice, reference Figure 6a-6c 7a-7b, the hollow body 210 is subjected to a force directed to the left side of the drawing, while the pin 450 is subjected to a force directed to the right side of the drawing. Therefore, the first contact blade 61 rigidly connected to the hollow body 210 is also subjected to a force directed to the left side of the drawing, while the second contact blade 62 rigidly connected to the pin 450 is also subjected to a force directed to the right side of the drawing. Due to this combination of forces, a traction force in general between the first contact blade 61 and the second contact blade 62 is obtained.

[0112] Therefore, in the overall embodiment of the present invention, the spacer 20, 200 may include a hollow body 21, 210 extending longitudinally in a direction transverse to the contact blades, and a first end of the longitudinal extension direction thereof is rigidly fixed to one contact blade; the spacer 20, 200 may also include a coupling element 40, 400 extending longitudinally in a direction transverse to the contact blades, and a first end of the longitudinal extension direction thereof is rigidly fixed to the other contact blade. The coupling element 40, 400 and the hollow body 21, 210 may be provided with a first protruding surface 46, 460 and a second protruding surface 26, 260 for operable connection with the elastic element 30, 300, respectively.

[0113] The design of the connecting elements 40, 400 and the hollow bodies 21, 210 and the spatial positioning of the elastic elements 30, 300 are such that when the elastic element 30, 300 is a compression type elastic element 30, it is spatially located between the first protruding surface 46 and the fixing point 41 of the connecting element 40 on the corresponding contact blade and between the second protruding surface 26 and the fixing point 28 of the hollow body 21 on the corresponding contact blade; when the elastic element 30, 300 is a traction type elastic element 300, the second protruding surface 260 is spatially located between the elastic element 300 and the fixing point 280 of the hollow body 210 on the corresponding contact blade, and the first protruding surface 460 is spatially located between the elastic element 300 and the fixing point 410 of the connecting element 400 on the corresponding contact blade.

[0114] With reference to the accompanying drawings, the movable contact assembly 1, 10, 50 of the present invention advantageously includes an adjustment device for adjusting the preload of the elastic element 30, 300, which can be, for example, a washer 80, a shim or a threaded device or other similar adjustment devices as shown in the figure. In practice, the preload of the elastic element 30, 300 can be easily adjusted by changing, for example, the number and / or thickness of the washer 80 disposed between the elastic device 30 and the retaining ring 26.

[0115] refer to Figure 4a-4b , 5a-5c, 6a-6c, in certain cases, when the medium voltage switch is provided with more than one fixed contact (for example, a first fixed contact 110 and a second fixed contact 120), the movable contact assembly 10, 50 of the present invention can be adjusted so that the first contact blade 61 and the second contact blade 62 are provided with corresponding third contact elements 73 and fourth contact elements 74.

[0116] The third and fourth contact elements 73, 74 are advantageously positioned facing each other at the second ends 611, 621 of the respective blades 61, 62 and are adapted to be coupled with corresponding second fixed contacts 120 of the medium voltage switch.

[0117] In such cases, the movable contact assembly 10, 50 also conveniently comprises first and second spacers 20, 200 of the type described above, positioned close to the first and second contact elements 71, 72 and said third and fourth contact elements 73, 74 respectively.

[0118] exist Figure 4a-4b In the embodiments shown in FIGS. 5a-5c and 6a-6c, the central portions 180 of the contact blades 61 and 62 are rotatably mounted on a fixed support, thereby allowing the contact blades 61 and 62 to rotate between a closed position shown in the figure - in which the first contact element 71, the second contact element 72, the third contact element 73 and the fourth contact element 74 are electrically connected to the corresponding first fixed contact element 110 and the second fixed contact element 120 of the medium voltage switch - and an open position, and vice versa.

[0119] The spacers 20, 200 are advantageously positioned close to the contact point so that the force exerted by the elastic elements 30, 300 on the contact system in the closed position can be maximized.

[0120] It can be clearly seen from the above description that the arrangement of the movable contact assembly of the present invention and the arrangement of the medium voltage switch (especially the isolating switch or the earthing switch or the combined isolating switch and the earthing switch) including the movable contact assembly as described herein fully achieve the intended goals and solve the above-mentioned problems of the medium voltage switch.

[0121] Numerous modifications may be made to the movable contact assembly, all of which fall within the scope of the appended claims. In practice, the materials used and, where appropriate, the dimensions and shapes may be chosen at will according to requirements and the state of the art.

Claims

1. A movable contact assembly (1, 10, 50) of a medium voltage switch, comprising a first contact blade (61) and a second contact blade (62) facing each other at a certain distance, the first contact blade (61) and the second contact blade (62) being provided with corresponding first contact elements (71) and second contact elements (72), the corresponding first contact elements (71) and second contact elements (72) being positioned facing each other at first ends (610, 620) of the corresponding contact blades (61, 62), wherein: The first contact element (71) and the second contact element (72) are suitable for connecting with the corresponding first fixed contact (110) of the medium voltage switch, and are characterized in that the movable contact assembly (1, 10, 50) at least includes a spacer (20, 200) interposed between the first contact blade (61) and the second contact blade (62), wherein the spacer (20, 200) includes a hollow body (21, 210) for accommodating an elastic element (30, 300), the elastic element (30, 300) having a first operating end (31, 310) operably connected to one of the first contact blade (61) and the second contact blade (62) and a second operating end (32, 320) operably connected to the other of the first contact blade (61) and the second contact blade (62), and the elastic element (30, 300) applies a traction force between the first contact blade (61) and the second contact blade (62).

2. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 1, wherein: The spacer (20, 200) is positioned adjacent to the first contact element (71) and the second contact element (72).

3. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 1 or 2, wherein: The elastic element (30, 300) is positioned substantially perpendicular to the first contact blade (61) and the second contact blade (62).

4. A medium voltage switch movable contact assembly (1, 10, 50) according to one or more of the preceding claims, wherein: The spacer (20, 200) includes a coupling element (40, 400) which is slidingly inserted into the hollow body (21, 210) and has a first end (41, 410) which is rigidly coupled to one of the first contact blade (61) or the second contact blade (62), and wherein the hollow body (21, 210) is rigidly coupled to the other of the first contact blade (61) or the second contact blade (62).

5. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 4, wherein: The first operating end (31, 310) of the elastic element (30, 300) is operably connected to one of the coupling element (40, 400) or the hollow body (21, 210), and the second operating end (32, 320) of the elastic element (30, 300) is operably connected to the other of the coupling element (40, 400) or the hollow body (21, 210).

6. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 4 or 5, wherein: The coupling element (40, 400) includes a pin (45, 450) having a first end (41, 410) rigidly coupled to one of the first contact blade (61) or the second contact blade (62) and a second end (42, 420) operably connected to the elastic element (30, 300).

7. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 6, wherein: The second end (42, 420) of the pin (45, 450) includes a first protruding surface (46, 460) located inside the hollow body (21, 210).

8. The medium voltage switch movable contact assembly (1, 10, 50) according to claim 7, wherein the second end (42, 420) of the pin (45, 450) comprises a first protruding surface (46, 460), the first protruding surface (46, 460) being operably connected to one of the first operating end (31, 310) or the second operating end (32, 320) of the elastic element (30, 300).

9. The movable contact assembly (1, 10, 50) of a medium voltage switch according to claim 8, wherein: The hollow body (21, 210) includes a second protruding surface (26, 260) operably connected to the other of the first operating end (31, 310) or the second operating end (32, 320) of the elastic element (30, 300).

10. The movable contact assembly (1, 10) of a medium voltage switch according to claim 9, wherein: The elastic element (30) is a compression spring interposed between the first protruding surface (46) and the second protruding surface (26), wherein the compression spring (30) has a first operating end (31) resting on the first protruding surface (46) and a second operating end (32) resting on the second protruding surface (26), and the compression spring (30) pushes the first protruding surface (46) and the second protruding surface (26) in opposite divergent directions.

11. The movable contact assembly (50) of a medium voltage switch according to claim 9, wherein: The elastic element (300) is a traction spring interposed between the first protruding surface (460) and the second protruding surface (260), and wherein the traction spring (300) has a first operating end (310) engaged with the first protruding surface (460) and a second operating end (320) engaged with the second protruding surface (260), and the traction spring (300) pulls the first protruding surface (460) and the second protruding surface (260) in opposite converging directions.

12. A movable contact assembly (1, 10, 50) for a Medium Voltage switch according to one or more of the preceding claims, further comprising adjustment means (80) for adjusting the preload of said elastic element (30, 300).

13. A medium voltage switch movable contact assembly (10, 50) according to one or more of the preceding claims, wherein: The first contact blade (61) and the second contact blade (62) are provided with corresponding third contact elements (73) and fourth contact elements (74), and the corresponding third contact elements (73) and fourth contact elements (74) are positioned facing each other at the second ends (611, 621) of the corresponding blades (61, 62), wherein the third contact elements (73) and the fourth contact elements (74) are suitable for connecting with the corresponding second fixed contacts (120) of the medium voltage switch, and wherein the movable contact assembly (10, 50) further comprises a first spacer and a second spacer in the spacer (20, 200), and the first spacer and the second spacer are positioned close to the first contact element (71) and the second contact element (72) and close to the third contact element (73) and the fourth contact element (74), respectively.

14. A Medium Voltage switch comprising a movable contact assembly (1, 10, 50) according to one or more of the preceding claims.

15. The medium voltage switch according to claim 14, wherein: The switch is a disconnector or an earthing switch or a combination of a disconnector and an earthing switch.

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