Mobile contact for a cut-off device

Abstract

A movable contact (20) is proposed for an electrical current interruption device (50), comprising: - a first conducting knife (1) and a second conducting knife (2), extending from parallel planes (P1,P2) separated by a distance between them, the conducting knives (1,2) being rotationally linked about a common axis of rotation (R), - a first and second spacer (3,4) configured to maintain a minimum distance between the first knife (1) and the second knife (2), wherein a cross-section (S1,S2) of each knife (1,2) is shaped to: - have an area equal to the area of ​​a reference rectangular cross-section (S1',S2') of the same length (a), and - have a second moment of area greater than the second moment of area of ​​the reference cross-section (S1',S2'), the second moment of area being determined with respect to an axis parallel to the transverse axis (T1,T2) of the knives (1,2). Figure of the abstract: Figure 3

Description

Title of the invention: Movable contact for a disconnecting device technical field

[0001] The present invention relates to the field of switching devices for medium-voltage electrical equipment, i.e., equipment with a nominal operating voltage between 1 and 52 kV. These switching devices allow the current to be interrupted or established in a medium-voltage electrical network. Prior art

[0002] Switching devices used in medium-voltage electrical networks may comprise a fixed contact and a rotating moving contact between at least two positions. One of the positions corresponds to a separation position between the fixed and moving contacts, known as the opening position, in which the current is interrupted in the electrical circuit. The other position corresponds to a position in which the fixed and moving contacts are in mechanical and electrical contact, known as the closing position, allowing current to flow in the circuit.

[0003] The moving contact generally comprises two elongated elements called knives, extending parallel to each other and spaced apart. When the moving contact is in the circuit closing position, a fixed contact is inserted between the opposite ends of the two moving knives and is brought into contact with each of the moving knives.

[0004] The electrodynamic forces generated by the flow of electric current cause the knives to experience an attractive force towards each other. This force tends to deform the knives, particularly when the intensity of the electric current is high, for example during a short circuit. This deformation of the blades tends to decrease the contact pressure between the blades and the fixed contact. Such a decrease in contact pressure increases the risk of electrical arcing and must be avoided.

[0005] It is known to connect the knives together by one or more rigid elements, in order to limit the deformation of the knives under the effect of electrodynamic forces and thus ensure the maintenance of a sufficient contact pressure between the knives and the fixed contact. However, the performance achieved may be insufficient to meet the increasing applicable requirements, for example short circuits with particularly high current intensity. Furthermore, the presence of these connecting elements adds weight to the moving contact, increases its cost price, and requires additional operations during assembly.

[0006] There is therefore a need for mobile contacts with improved characteristics, particularly in short-circuit withstand. Summary

[0007] To this end, the invention proposes a movable contact for an electrical current cutting-off device. The mobile contact includes: - a first conducting knife and a second conducting knife, each conducting knife extending longitudinally along a longitudinal axis, and transversely along a transverse axis, the longitudinal axis and the transverse axis of the first conducting knife defining a first plane, the longitudinal axis and the transverse axis of the second conducting knife defining a second plane, the first plane and the second plane being parallel to each other and distant from each other, the first conducting knife and the second conducting knife being linked in rotation around a common axis of rotation perpendicular to the first and second planes, - a first spacer and a second spacer arranged between the first knife and the second knife, configured to maintain a minimum distance between the first knife and the second knife, in which a cross-section of each knife is shaped to: - to have an area equal to the area of ​​a reference cross-section having a rectangular shape and the same length, the length being measured parallel to the transverse axis, and - have a second moment of area greater than the second moment of area of ​​the reference cross section, the second moment of area being determined with respect to an axis parallel to the transverse axis of the knives.

[0008] When a current flows through the moving contact, the electromagnetic forces generated by the electric current, which flows in the same direction in the two conducting blades arranged parallel to each other, cause each blade to experience an attractive force towards the other. Each blade thus comes to rest against the spacers. In the case of a high current, such as a short-circuit current, the portion of the blades between the spacers tends to deform and take on a curved shape. The deformation is greatest at the point equidistant between the spacers, which are the bearing surfaces for the blades. A first spacer is positioned near the axis of rotation of the moving contact, and a second spacer is positioned near the area that may come in contact with the fixed contact. These two spacers are therefore close to the longitudinal ends of the knives. Due to their deformation, the gap between the blades at each end tends to increase, which reduces the contact pressure with the fixed contact. When the contact pressure becomes insufficient, electrical arcs can form, and the moving contact may also open spontaneously due to the decrease in frictional forces holding it closed. Therefore, excessive variation in the gap between the contact ends must be avoided. According to prior art, each knife has the form of a flat blade with a rectangular cross-section. The moving contact includes a third spacer, positioned between the first and second spacers, approximately equidistant from each. This third spacer helps to limit the deformation of the knives, as it provides an additional bearing surface. This third spacer has the disadvantage of not allowing the knives to clamp onto the fixed contact, which would increase the contact pressure. Furthermore, the third spacer increases the mass and inertia of the moving contact, complicating its manufacture and increasing its cost. According to the invention, the conductive blades have a cross-section with a different rectangular shape, so as to increase their resistance to deformation under the effect of electromagnetic forces. Thanks to this increased resistance, it is possible to eliminate the third spacer. The moving contact is thus easier to assemble and can be made lighter. The electrical current flow capacity remains unchanged, since only the shape of the cross-section varies, its area remaining constant.

[0009] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0010] Each conducting knife extends along the transverse axis between a first longitudinal edge and a second longitudinal edge. To obtain a cross-section of each knife shaped as indicated above, a cross-section of each knife may include, in particular: - a first portion adjacent to the first longitudinal edge of said knife, - a second portion adjacent to the second longitudinal edge of said knife, - a third portion connecting the first portion to the second portion, and: - the thickness of the first portion and the thickness of the second portion are greater than the thickness of the third portion.

[0011] According to one aspect of the moving contact, the first longitudinal edge of a knife is part of the first portion of said knife.

[0012] Similarly, the second longitudinal edge of a knife is part of the second portion of said knife.

[0013] The thickness of the third portion of the cross-section of each knife can vary along the longitudinal axis.

[0014] Similarly, the thickness of the first portion of the cross-section of each knife can vary along the longitudinal axis.

[0015] Similarly, the thickness of the second portion of the cross-section of each knife can vary along the longitudinal axis.

[0016] According to one embodiment of the moving contact, the thickness of the third portion is less than 60% of the thickness of the first portion, preferably less than 50% of the thickness of the first portion, preferably still less than 40% of the thickness of the first portion, the thickness being measured parallel to a direction perpendicular to both the longitudinal axis and the transverse axis.

[0017] By making a clear difference between the thickness of the third portion and the thickness of the other two portions, the flexural strength of the knives can be considerably increased.

[0018] According to one embodiment of the moving contact, the thickness of the third portion is greater than 10% of the thickness of the first portion, preferably greater than 20% of the thickness of the first portion, preferably even greater than 30% of the thickness of the first portion.

[0019] Similarly, the thickness of the third portion is less than 60% of the thickness of the second portion, preferably less than 50% of the thickness of the second portion, preferably even less than 40% of the thickness of the second portion.

[0020] Similarly, the thickness of the third portion is greater than 10% of the thickness of the second portion, preferably greater than 20% of the thickness of the second portion, preferably even greater than 30% of the thickness of the second portion.

[0021] According to one embodiment, the mobile contact comprises: - a first guide bar linked to the first knife, extending along an axis parallel to the axis of rotation, configured to allow the second knife to slide relative to the first knife, - a first elastic element configured to apply an elastic force tending to bring the knives closer together in a direction parallel to the axis of rotation, - a second guide bar linked to the first knife, extending along an axis parallel to the axis of rotation, configured to allow sliding of the second knife relative to the first knife, - a second elastic element configured to apply an elastic force tending to bring the knives closer together in a direction parallel to the axis of rotation, and the first spacer and the second spacer are opposite each other in a direction parallel to the longitudinal axis of the knives.

[0022] In other words, the space longitudinally between the first spacer and the second spacer is devoid of any other spacer.

[0023] The moving contact is thus lightened and its assembly is facilitated.

[0024] In other words, the moving contact comprises exactly two spacers.

[0025] Since the deformation of the knives is minimized by the proposed geometry of their cross-section, the forces pulling the knives towards each other increase the contact pressure with the fixed contact. This prevents the formation of parasitic electrical arcs. Furthermore, the increased friction between the knives and the fixed contact helps to maintain the position of the moving contact and prevents its spontaneous reopening.

[0026] The part of the first knife extending longitudinally between the first spacer and the second spacer is thus free, that is to say, devoid of a connecting element that can oppose a bending of the first knife in a direction parallel to the axis of rotation. The same applies to the second knife.

[0027] The first guide bar and the second guide bar are offset from each other along the longitudinal axis of the knives.

[0028] The second knife can slide along the first guide bar and along the second guide bar.

[0029] According to one embodiment, the first guide bar and the first spacer are concentric.

[0030] The first guide bar and the first elastic element are concentric.

[0031] According to one embodiment, the first guide bar includes a shoulder bearing on the first knife.

[0032] The first guide bar passes through the first knife and the second knife in a direction parallel to the axis of rotation.

[0033] According to one embodiment, a first support cup is rigidly linked to the first guide bar.

[0034] A first end of the first elastic element rests on the first support cup, and a second end of the first elastic element rests on the second knife.

[0035] According to one embodiment, the first elastic element is pre-stressed. The first elastic element tends to push the second knife towards the first knife.

[0036] The first spacer is arranged between the two knives in a direction parallel to the axis of rotation, and surrounds the first guide bar.

[0037] The first spacer is cylindrical in shape.

[0038] A first axial surface of the first spacer can bear on the first knife and a second axial surface of the first spacer can bear on the second knife.

[0039] Similarly, the second guide bar and the second spacer are concentric.

[0040] The second guide bar and the second elastic element are concentric.

[0041] The second guide bar includes a shoulder bearing on the second knife.

[0042] The second guide bar passes through the first knife and the second knife in a direction parallel to the axis of rotation.

[0043] A second support cup is rigidly linked to the second guide bar.

[0044] A first end of the second elastic element rests on the second support cup, and a second end of the second elastic element rests on the second knife.

[0045] The second elastic element is pre-stressed. The second elastic element tends to push the second knife towards the first knife.

[0046] The second spacer is arranged between the two knives in a direction parallel to the axis of rotation, and surrounds the second guide bar.

[0047] The second spacer is cylindrical in shape.

[0048] A first axial surface of the second spacer can bear on the first knife and a second axial surface of the second spacer can bear on the second knife.

[0049] According to one embodiment, the first portion of a cross-section of each knife is convex in shape.

[0050] The second portion of a cross-section of each knife is convex in shape.

[0051] The third portion of each knife extends continuously on either side of the longitudinal axis of each knife.

[0052] According to one embodiment of the moving contact, the first portion and the second portion of a cross-section of each knife are symmetrical to each other with respect to the longitudinal axis of said knife.

[0053] According to one embodiment, the first portion of a cross-section of each knife comprises a substantially semi-circular part, and a first longitudinal edge of each knife forms part of the substantially semi-circular part of the first portion.

[0054] A radius of curvature of the first substantially semi-circular part of the first portion is between 30% and 60% of the thickness of each knife.

[0055] Similarly, the second portion of each knife comprises a substantially semicircular part, and a second longitudinal edge of each knife forms part of the substantially semicircular part of the second portion.

[0056] A radius of curvature of the substantially semi-circular part of the second portion is between 30% and 60% of the thickness of each knife.

[0057] The knives thus have a rounded profile near the longitudinal edges. Compared to conventional knives with a substantially rectangular cross-section, this rounded profile helps to limit dielectric stresses at the edges of the knives.

[0058] According to one embodiment of the moving contact, the third portion of each knife is substantially rectangular in shape.

[0059] The first knife and the second knife have the same length, measured parallel to the longitudinal axis.

[0060] The first knife and the second knife have the same width, measured parallel to the transverse axis.

[0061] The first knife and the second knife have the same thickness, measured parallel to the axis perpendicular to the longitudinal axis and to the transverse axis.

[0062] According to one embodiment of the moving contact, the first knife and the second knife are symmetrical to each other with respect to a plane parallel to the first plane defined by the longitudinal axis and the transverse axis of the first conducting knife.

[0063] According to one embodiment, the first knife comprises a first face opposite the second knife in a direction parallel to the axis of rotation, and the first face of the first knife is flat.

[0064] Similarly, the second knife may include a first face opposite the first knife in a direction parallel to the axis of rotation, the first face of the second knife being flat.

[0065] Each knife comprises two longitudinal edges and two transverse edges. According to one embodiment of the moving contact, each knife comprises: - a first portion of thickness less than a predetermined threshold, the first portion extending longitudinally along the longitudinal axis and transversely on either side of the longitudinal axis, and - a second part with a thickness greater than the predetermined threshold, the second part surrounding the first part, the second part forming the longitudinal edges of the knife and the transverse edges of the knife.

[0066] Each knife is thus formed of a tapered portion extending longitudinally and transversely. This tapered portion is extended by a ridge thicker than the tapered portion itself. The tapered portion is surrounded by the ridge-shaped part.

[0067] In other words, the longitudinal edges of each knife form part of the second part, having an increased thickness.

[0068] The predetermined threshold is for example between 30% and 60% of the thickness of each knife.

[0069] According to one embodiment of the movable contact, each knife comprises a through recess extending longitudinally along the longitudinal axis and transversely on either side of the longitudinal axis, the length of the recess being between 20% and 80% of the length of the knife, and the width of the recess being between 25% and 75% of the width of the knife.

[0070] The through recess may be substantially rectangular in shape.

[0071] The invention also relates to an electrical current interruption device, comprising: - a first section of electrical line comprising a first electrical conductor and a movable contact as described previously, the contact being movable in rotation relative to the first electrical conductor, - a second section of power line comprising a second electrical conductor and a fixed contact attached to the second electrical conductor, the movable contact being configured to be moved between: - a first position, called the opening position, in which the moving contact is separated from the fixed contact so as to prevent the flow of electric current between the first and second sections of the power line, and - a second position, called the closing position, in which the moving contact is in contact with the fixed contact so as to allow the flow of electric current between the first and second sections of the power line.

[0072] According to one embodiment, the electrical current interruption device is a medium- or high-voltage switch.

[0073] The invention also relates to a medium voltage electrical device, configured to selectively establish or interrupt the current in a medium voltage electrical network comprising three phases, including an electrical current interruption device as described above disposed respectively on each of the phases of the electrical network.

[0074] The electrical device may be, for example, a line disconnector or a circuit breaker. Brief description of the drawings

[0075] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0076] [Fig. 1] is a schematic representation of an electrical device comprising a switching device, in the position of switching off the electric current,

[0077] [Fig.2] is a schematic representation of the electrical device of [Fig.1], in the position of electric current flow,

[0078] [Fig.3] is a perspective view of a movable contact according to a first embodiment of the invention,

[0079] [Fig.4] is a partial, perspective view of the moving contact of [Fig.3],

[0080] [Fig.5] is a top view of the moving contact of [Fig.3],

[0081] [Fig.6] is a cross-section of the moving contact of [Fig.3],

[0082] [Fig.7] is another partial cross-section of the moving contact of [Fig.3],

[0083] [Fig.8] is a cross-sectional view of a conductive knife of the moving contact of [Fig.3],

[0084] [Fig.9] is a perspective view of a conductive knife of the cutting device of the [Fig.3],

[0085] [Fig. 10] is another partial cross-section of the moving contact of [Fig. 3],

[0086] [Fig. 11] is a schematic top view of the moving contact of [Fig. 3],

[0087] [Fig. 12] is a perspective view of a conductive knife of a movable contact according to a second embodiment of the invention. Description of the implementation methods

[0088] To facilitate reading the figures, the various elements are not necessarily drawn to scale. In these figures, identical elements bear the same reference numerals. Certain elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate similar, but not identical, elements or parameters. This indexing does not imply a priority of one element or parameter over another, and the designations may be interchanged. When it is specified that a device comprises a given element, this does not exclude the presence of other elements in that device.

[0089] Figures 1 and 2 show a medium voltage electrical device 100, configured to selectively establish or interrupt the current in a medium voltage electrical network. The electrical network has three phases Phi, Ph2, Ph3. The electrical device 100 includes an electrical current interruption device 50, 50', 50" disposed respectively on each of the phases Phi, Ph2, Ph3 of the electrical network.

[0090] The three shut-off devices 50, 50', 50" are arranged here in a sealed enclosure 90 maintained under pressure. The gas contained in the enclosure can be an inert gas or air.

[0091] According to the illustrated example, the electrical current interruption device 50 is a medium or high voltage switch. Electrical device 100 can also be a line disconnector, or a circuit breaker.

[0092] The electrical current interruption device 50 comprises a first portion of electrical line 25-1 including a first electrical conductor 19 and a movable contact 20. The contact 20 is movable in rotation relative to the first electrical conductor 19 around which the movable contact 20 is articulated. The electrical current interruption device 50 includes a second portion of electrical line 25-2 comprising a second electrical conductor 22 and a fixed contact 21 attached to the second electrical conductor 22. Mobile contact 20 is configured to be moved between: - a first position PI, called the opening position, in which the moving contact 20 is separated from the fixed contact 21 so as to prevent the passage of electric current between the first section of the power line 25-1 and the second section of the power line 25-2, and - a second position P2 called the closing position in which the moving contact 20 is in contact with the fixed contact 21 so as to allow a passage of electric current between the first portion of the electric line 25-1 and the second portion of the electric line 25-2.

[0093] In [Fig. 1], the moving contact 20 is in the PI position, and no current flows between the first portion of the power line 25-1 and the second portion of the power line 25-2. In [Fig.2], the moving contact 20 is in position P2. An electric current, schematically represented by the dashed arrows designated by the sign f, flows between the first portion of the electric line 25-1 and the second portion of the electric line 25-2, passing successively through the moving contact 20 and the fixed contact 21. A control mechanism 80, which will not be detailed, allows the movable contact 20 to be moved alternately from position PI to position P2, and from position P2 to position PL The control mechanism 80 simultaneously moves the moving contact 20' and the moving contact 20'', which are respectively part of the breaking device 50' and the breaking device 50'.

[0094] The proposed electrical current interruption device 50 will now be described in detail.

[0095] Figure 3 shows a general view of a first embodiment of the proposed movable contact 20. The movable contact 20 is a contact for an electrical current interruption device 50 such as that shown schematically in Figures 1 and 2. The moving contact 20 comprises a first conducting knife 1 and a second conducting knife 2, each conducting knife 1, 2 extending longitudinally along a longitudinal axis D1, D2, and transversely along a transverse axis T1, T2. The longitudinal axis D1 and the transverse axis T1 of the first conducting knife 1 define a first plane P1. The longitudinal axis D2 and the transverse axis T2 of the second conducting knife 2 define a second plane P12. The first plane P1 and the second plane P12 are parallel to each other and separated by a distance between them. The first conducting knife 1 and the second conducting knife 2 are linked in rotation around a common axis of rotation R perpendicular to the first plane Pli and to the second plane P12. The moving contact 20 comprises a first spacer 3 and a second spacer 4 arranged between the first knife 1 and the second knife 2, configured to maintain a minimum distance between the first knife 1 and the second knife 2. A cross-section S1,S2 of each knife 1,2 is shaped to: - have an area equal to the area of ​​a reference cross-section S1',S2' having a rectangular shape and the same length L, the length a being measured parallel to the transverse axis T1,T2, and - have a second moment of area greater than the second moment of area of ​​the reference cross section S1',S2', the second moment of area being determined with respect to an axis parallel to the transverse axis T1,T2 of the knives 1,2.

[0096] When a current flows through the moving contact 20, the electromagnetic forces generated by the electric current, which flows in the same direction in the two conducting knives 1, 2, arranged parallel to each other, cause each knife to experience an attractive force towards the other. These forces are schematically represented by the symbol fe in [Fig. 11]. Each knife 1,2 thus rests on the spacers arranged between the knives. In the case of a high current, such as a short-circuit current, the portion of the blades located longitudinally between the spacers tends to deform and take on a curved shape, schematically represented by dashed lines in [Fig. 11]. The spacers provide support areas for the blades. The deformation of the conductive blades is greatest in the portions located approximately equidistant between the spacers. A first spacer 3 is positioned near the axis of rotation of the moving contact 20, and a second spacer 4 is positioned near the area that can come into contact with the fixed contact. These two spacers 3,4 are therefore close to the longitudinal ends of the knives. Due to their deformation under the effect of electromagnetic forces, the spacing of the knives 1,2 at each end tends to increase, which reduces the contact pressure between the conductive knives and the fixed contact 21. This reduction in contact pressure is problematic because it promotes the formation of electrical arcs and spontaneous reopening of the moving contact 20. Indeed, the frictional forces with the fixed contact 21, which help to keep the moving contact 20 in the closed position, may become insufficient. Therefore, excessive variation in the gap between the ends of the conductive blades must be avoided. According to the prior art, each conductive knife 1,2 has the shape of a flat blade with a rectangular cross-section. The moving contact 20 includes a third spacer, arranged between the first spacer 3 and the second spacer 4 in the longitudinal direction, substantially equidistant from each spacer 3,4. This third spacer helps to limit the deformation of the conductive knives, since it provides an additional bearing area in addition to the supports provided by the first and second spacers. This third spacer has the disadvantage of not providing a clamping effect on the knives against the fixed contact 21, which would increase the contact pressure. According to the invention, the conductive knives 1, 2 have a cross-section SI, S2 with a shape different from rectangular, so as to increase their resistance to deformation under the effect of electromagnetic forces. Thanks to this increased resistance, it is possible to eliminate the third spacer while ensuring that the conductive knives 1, 2 retain a substantially straight shape. Under these conditions, the electrodynamic forces applied to the conducting knives 1,2 tend to bring the knives closer together without changing their shape, which makes it possible to increase the contact pressure with the fixed contact 21. The performance of the mobile contact 20 is improved, particularly for short-circuit resistance. The cross-sectional area remains the same as that of a conventional knife with a rectangular cross-section, so the current-carrying capacity remains unchanged. Indeed, the current-carrying capacity of an electrical conductor is directly proportional to the cross-sectional area of ​​that conductor through which the current flows.

[0097] Throughout the description, the geometric characteristics applicable to one conducting knife are also applicable to the other conducting knife.

[0098] The cross-section S1,S2 of each knife 1,2 is shaped to have the same area as a reference cross-section S1',S2'. This reference cross-section S1',S2' is rectangular and has a length M identical to that of the actual cross-section S1,S2 of the knife 1,2 under consideration. This reference cross-section S1',S2', being rectangular, has a constant width. Figure 7 represents the proposed cross-section for each of the conducting knives 1, 2. To simplify the reading of Figure 7, the reference cross-section is shown only for the first knife 1, and is represented by a dotted line designated by the sign SI'. Part A of [Fig. 10] illustrates the proposed cross-section S2 for the second conductive knife 2 taken in isolation. Part B of [Fig. 10] illustrates the reference cross-section S2' for a conductive knife 2. On this [Fig. 10], the length M of the rectangular surface S2' of part B is the same as that of the section S2 of part A. The dimension E, corresponding to the thickness of contact 2 of part A, is greater than the thickness E' of contact 2 of part B. The cross-section S2 and the cross-section S2' have the same area, so as to ensure the same effective current passage area.

[0099] Each conducting knife 1,2 extends along the transverse axis T1,T2 between a first longitudinal edge B1_1,B1_2 and a second longitudinal edge B2_1,B2_2. In other words, the conducting knife 1 extends along the transverse axis Tl between a first longitudinal edge Bl_l and a second longitudinal edge B2_l. The conducting knife 2 extends along the transverse axis T2 between a first longitudinal edge B 1_2 and a second longitudinal edge B2_2. To obtain a cross-section S1,S2 of each knife 1,2 shaped as indicated above, a cross-section S1,S2 of each knife 1,2 comprises here: - a first portion T1_1,T1_2 adjacent to the first longitudinal edge B1_1,B1_2 of said knife 1,2, - a second portion T2_1,T2_2 adjacent to the second longitudinal edge B2_1,B2_2 of said knife 1,2, - a third portion T3_1,T3_2 linking the first portion T1_1,T1_2 to the second portion T2_1,T2_2, and: - the thickness el_l,el_2 of the first portion T1_1,T1_2 and the thickness e2_l,e2_2 of the second portion T2_1,T2_2 are greater than the thickness e3_l,e3_2 of the third portion T3_1,T3_2. The different portions and corresponding thicknesses are illustrated in particular on [Fig.6].

[0100] The thickness E of a conducting knife 1,2, as well as the thickness of the different portions defined above for the cross section SI, S2 of each conducting knife 1,2, is measured parallel to a direction perpendicular to both the longitudinal axis D1,D2 and the transverse axis T1,T2. The thickness is thus measured along a direction parallel to the axis of rotation R of the moving contact 20.

[0101] Fig. 10 represents the reference frame used to calculate the second moment of area of ​​the proposed cross-section S2, as well as of the reference cross-section S2'. The second moment of area is determined with respect to an x-axis parallel to the transverse axis T1,T2 of the knives 1,2. In [Fig. 10], the cross-section S2 is taken at a given point on the longitudinal axis D2 of the second knife. The symbol G designates the barycenter of this cross-section S2 and forms the origin of the coordinate system. In this figure, the axis designated by the sign y passes through the barycenter G and is parallel to the axis of rotation R. The axis designated by the sign x passes through the barycenter G and is parallel to the transverse axis T2 of the second knife 2. For the rectangular reference surface S2', the centroid G' is equidistant from the opposite edges of the rectangle, both along the x-axis and the y-axis.

[0102] The cross-section is divided into infinitesimal surface elements dA. An infinitesimal element is located at a distance dy from the x-axis, and the second moment of area Ix x determined with respect to the x-axis is calculated by the formula: [Math. 1] d2 hx = Jj^dA

[0103] The area dA of an infinitesimal element can also be written: dA = x * dy, which gives: [Math. 2] r / 2 ixx = \ny2*x*dy

[0104] The quadratic moment of inertia Ix x characterizes the ability of the conducting knife 2 to resist the bending caused by electromagnetic forces which tend to bring the two conducting knives closer together and to bend the knife with respect to its transverse axis.

[0105] In [Fig. 10], the infinitesimal element of area dA is schematically represented by the surface hatched. Points 11 and 12 are the points furthest from the center of gravity G along the y-axis. Points ml and m2 are the points furthest from the center of gravity G along the x-axis. According to the example in [Fig. 10], the cross-section S2 of the second knife 2 is symmetrical with respect to the y-axis.

[0106] The first longitudinal edge B1_1,B1_2 of a knife 1,2 is part of the first portion T1_1,T1_2 of said knife 1,2. Similarly, the second longitudinal edge B2_1,B2_2 of a knife 1,2 is part of the second portion T2_1,T2_2 of said knife 1,2.

[0107] The thickness e3_l,e3_2 of the third portion T3_1,T3_2 of the cross-section S1,S2 of each knife 1,2 can vary along the longitudinal axis D1,D2. The thickness e1_l,e2 of the first portion T1_1,T1_2 of the cross-section S1,S2 of each knife 1,2 can vary along the longitudinal axis D1,D2. Similarly, the thickness e2_l,e2_2 of the second portion T2_1,T2_2 of the cross-section S1,S2 of each knife 1,2 can vary along the longitudinal axis D1,D2. As shown in particular in [Fig.3] and [Fig.4], notches can be formed in the periphery of knives 1,2.

[0108] According to the illustrated example, in particular on [Fig.6], the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 60% of the thickness el_l,el_2 of the first portion T1_1,T1_2. Preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 50% of the thickness el_l,el_2 of the first portion T1_1,T1_2. More preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 40% of the thickness el_l,el_2 of the first portion T1_1,T1_2. The thickness is measured parallel to a direction perpendicular to both the longitudinal axis D1,D2 and the transverse axis T1,T2. The thickness is thus measured parallel to the axis of rotation R of the moving contact 20.

[0109] Establishing a clear difference between the thickness e3_l,e3_2 of the third portion T3_1,T3_2 and the thickness of the other two portions makes it possible to considerably increase the resistance to bending of the conducting knives 1,2. These can thus maintain a substantially straight shape even when they are traversed by a short-circuit current.

[0110] According to the illustrated example, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 60% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2. Preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 50% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2. Preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is less than 40% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2.

[0111] Similarly, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 10% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2. Preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 20% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2. More preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 30% of the thickness e2_l,e2_2 of the second portion T2_1,T2_2.

[0112] According to the illustrated example, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 10% of the thickness el_l,el_2 of the first portion T1_1,T1_2. Preferably, this thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 20% of the thickness el_l,el_2 of the first portion T1_1,T1_2. More preferably, the thickness e3_l,e3_2 of the third portion T3_1,T3_2 is greater than 30% of the thickness el_l,el_2 of the first portion T1_1,T1_2.

[0113] We will now describe the general structure of the mobile contact 20.

[0114] As shown in [Fig.3] and [Fig.5], the mobile contact 20 comprises: - a first guide bar 5 linked to the first knife 1, extending along a axis D5 parallel to the axis of rotation R, configured to allow sliding of the second knife 2 relative to the first knife 1, - a first elastic element 7 configured to apply an elastic force tending to bring the knives 1,2 closer together in a direction parallel to the axis of rotation R. Mobile contact 20 includes: - a second guide bar 6 linked to the first knife 1, extending along a axis D6 parallel to the axis of rotation R, configured to allow sliding of the second knife 2 relative to the first knife 1, - a second elastic element 8 configured to apply an elastic force tending to bring the knives 1,2 closer together in a direction parallel to the axis of rotation R. The first spacer 3 and the second spacer 4 are opposite each other in a direction parallel to the longitudinal axis D1,D2 of the knives.

[0115] It is understood here that a straight line segment originating from the first spacer 3 and directed towards the second spacer 4 parallel to the longitudinal direction passes through the second spacer 4 without passing through any other element. Similarly, a straight line segment originating from the second spacer 4 and directed towards the first spacer 3 in a direction parallel to the longitudinal direction passes through the first spacer 3 without passing through any other element. In other words, as can be seen particularly in [Fig.5], the space longitudinally between the first spacer 3 and the second spacer 4 is devoid of any other spacer.

[0116] The electromagnetic forces generated by the flow of electric current between the first electrical conductor 19 and the fixed contact 21 tend to bring the conductive blades 1, 2 closer together. Thanks to their profile, the conductive blades 1, 2 resist bending forces and maintain a substantially straight shape. The electromagnetic forces thus tend to increase the contact pressure at the fixed contact 21 and the first electrical conductor 19. Figure 11 schematically illustrates the electromagnetic forces tending to bring the conducting knives 1 and 2 closer together. The symbol C1 denotes the area of ​​the first knife 1 where the contact pressure with the fixed contact 21 is increased. Similarly, the symbol C2 denotes the area of ​​the second knife 2 where the contact pressure with the fixed contact 21 is increased. The risk of formation of parasitic electrical arcs is avoided. Similarly, the risks of spontaneous reopening of mobile contact 20 are avoided. The current flow capacity between the knives 1,2 and the fixed contact 21 is thus increased. Furthermore, the absence of an intermediate spacer between the first spacer 3 and the second spacer 4 makes it possible to lighten the mobile contact 20, and also to facilitate its assembly.

[0117] The part of the first knife 1 extending longitudinally between the first spacer 3 and the second spacer 4 is thus free, that is to say, devoid of a connecting element that can oppose a bending of the first knife 1 in a direction parallel to the axis of rotation R. The same applies to the second knife 2.

[0118] The first guide bar 5 and the second guide bar 6 are offset from each other along the longitudinal axis D1,D2 of the knives 1,2. The second knife 2 can slide along the first guide bar 5 and along the second guide bar 6.

[0119] When the moving contact 20 moves from the open position PI to the closed position P2, the fixed contact 21 is inserted between the first conducting knife 1 and the second conducting knife 2. This tends to move the conducting knives apart. The second conducting knife 2 slides along the guide bars 5, 6, further compressing the elastic elements 7, 8.

[0120] When the moving contact 20 moves from the closed position P2 to the open position PI, the fixed contact 21 is cleared of the space between the first conductive knife 1 and the second conductive knife 2. The knives 1, 2 can thus They are brought closer together by the force applied by the elastic elements 7, 8, which release their potential energy. The second conducting knife 2 slides along the guide bars 5, 6, until its movement is blocked by the spacers 3, 4, which then act as a stop.

[0121] According to the illustrated example, the first guide bar 5 and the first spacer 3 are concentric. The first guide bar 5 and the first elastic element 7 are concentric.

[0122] According to the illustrated example, the first guide bar 5 includes a shoulder bearing against the first knife 1. This shoulder allows the first guide bar 5 to be locked in translation relative to the first knife 1, in a direction of movement oriented towards the second knife 2.

[0123] The first guide bar 5 passes through the first knife 1 and the second knife 2 in a direction parallel to the axis of rotation R.

[0124] As particularly visible in [Fig.4], the first knife 1 includes a first through orifice 9_1 receiving the first guide bar 5. The first knife 1 includes a second through orifice 10_l receiving the second guide bar 6.

[0125] A first support cup 11 is rigidly linked to the first guide bar 5. A first end 7a of the first elastic element 7 rests on the first support cup 11. A second end 7b of the first elastic element 7 rests on the second knife 2. The first elastic element 7 is here a helical spring.

[0126] The first elastic element 7 is here pre-stressed. The first elastic element 7 tends to push the second knife 2 towards the first knife 1.

[0127] The first support cup 11 is screwed onto the first guide bar 5. The shoulder of the first guide bar 5 includes a slot allowing the first guide bar 5 to be screwed into the first support cup 11. The relative position of the first support cup 11 along the guide bar can thus be adjusted, which allows the preload applied by the first elastic element 7 to be set.

[0128] A second support cup 12 is rigidly linked to the second guide bar 6. A first end 8a of the second elastic element 8 rests on the second support cup 12, and a second end 8b of the second elastic element 8 rests on the second knife 2. The second elastic element 8 is here a helical spring. The assembly of the second support cup 12 and the second guide bar 6 is carried out in the same way as for the assembly of the first support cup 11 and the first guide bar 5. The second elastic element 8 is pre-stressed. The second elastic element 8 tends to push the second knife 2 towards the first knife 1.

[0129] The first guide bar 5 and the second guide bar 6 may be identical. Similarly, the first support cup 11 and the second support cup 12 may be identical. The first elastic element 7 and the second elastic element 8 can also be identical.

[0130] The first spacer 3 is arranged between the two knives 1,2 in a direction parallel to the axis of rotation R, and surrounds the first guide bar 5. The first spacer 3 is cylindrical in shape. A first axial surface of the first spacer 3 can bear on the first knife 1 and a second axial surface of the first spacer 3 can bear on the second knife 2.

[0131] Similarly: The second guide bar 6 and the second spacer 4 are concentric. The second guide bar 6 and the second elastic element 8 are concentric. The second guide bar 6 includes a shoulder bearing against the second knife 2. The second guide bar 6 passes through the first knife 1 and the second knife 2 in a direction parallel to the axis of rotation R20.

[0132] The second knife 2 includes a first through hole 9_2 receiving the first guide bar 5. The second knife 2 includes a second through hole 10_2 receiving the second guide bar 6.

[0133] Each through orifice 9_1, 9_2, 10_1, 10_2 is here cylindrical, with a diameter slightly greater than the diameter of the guide bars 5,6 so as to allow the passage of the guide bars 5,6 as well as easy sliding of the second guide knife 2 along the guide bars 5,6. Each orifice through 9_1, 9_2, 10_l, 10_2 is formed in a portion of material that is part of the third portion T3_l, T3_2. As can be seen particularly in [Fig.8], the through holes allowing the passage of the guide bars are made in areas of increased thickness compared to the neighboring areas along the longitudinal axis D1,D2. The axis of each through orifice intersects the longitudinal axis D1,D2 of the conducting knife considered.

[0134] The second spacer 4 is arranged between the two knives 1,2 in a direction parallel to the axis of rotation R, and surrounds the second guide bar 6. The second spacer 4 is cylindrical in shape.

[0135] A first axial surface of the second spacer 4 can bear on the first knife 1 and a second axial surface of the second spacer 4 can bear on the second knife 2.

[0136] When the movable contact 20 is in the open position, the elastic force developed by the second elastic element 8 keeps each of the two knives 1,2 against the second spacer 4. Indeed, in the absence of a fixed contact 21 between the two knives, the second spacer 4 prevents the knives from coming into contact with each other and ensures a minimum distance between the knives 1,2. This minimum distance is slightly less than the size of the fixed contact 21, so as to allow easy insertion of the fixed contact 21 at the next closing operation of the movable contact 20. The edge of each knife 1,2 is chamfered to facilitate the insertion of the fixed contact 21 between the two knives.

[0137] According to the illustrated example, the first portion T1_1,T1_2 of a cross-section S1,S2 of each knife 1,2 is convex in shape. Similarly, the second portion T2_1,T2_2 of a cross-section S1,S2 of each knife 1,2 is convex in shape.

[0138] The third portion T3_1,T3_2 of each knife 1,2 extends continuously on either side of the longitudinal axis D1,D2 of each knife. In other words, the third portion T3_1,T3_2 is formed as a single unit, that is to say, it forms an uninterrupted block. When the cross-section produced passes through an orifice 9_1, 9_2 allowing the passage of guide bar 5, the third portion T3_1,T3_2 is formed in two parts separated from each other by a section of this orifice. The same applies when the cross-section produced passes through an orifice 10_l, 10_2 allowing the passage of guide bar 6.

[0139] According to the illustrated example, the first portion T1_1,T1_2 and the second portion T2_1,T2_2 of a cross-section S1,S2 of each knife 1,2 are symmetrical to each other with respect to the longitudinal axis D1,D2 of said knife 1,2.

[0140] According to an exemplary embodiment, the first portion T1_1,T1_2 of a cross-section S1,S2 of each knife 1,2 comprises a substantially semi-circular part, and a first longitudinal edge B1_1,B1_2 of each knife 1,2 is part of the substantially semi-circular part of the first portion T1_1,T1_2.

[0141] A radius of curvature rl of the first substantially semicircular part of the first portion T1_1,T1_2 is between 30% and 60% of the thickness E of each knife 1,2.

[0142] Similarly, the second portion T2_1,T2_2 of each knife 1,2 comprises a substantially semicircular part, and a second longitudinal edge B2_1,B2_2 of each knife 1,2 is part of the substantially semicircular part of the second portion T2_1,T2_2.

[0143] A radius of curvature r2 of the substantially semi-circular part of the second portion T2_1,T2_2 is between 30% and 60% of the thickness E of each knife 1,2. On [Fig.7], the sign V 1_2 designates the substantially semicircular part of the first portion T1_2 of the cross section S2 of the second knife 2, and the sign V2_2 designates the substantially semicircular part of the second portion T2_2 of the cross section S2 of the second knife 2.

[0144] The knives 1,2 thus have a rounded profile near their longitudinal edges. Compared to conventional knives with a substantially rectangular cross-section, this rounded profile helps to limit dielectric stresses at the edges of the knives, in addition to increasing their rigidity.

[0145] According to the illustrated example, the third portion T3_1,T3_2 of each knife 1,2 is substantially rectangular in shape. In [Fig.7], the dotted lines designated by the symbol h indicate the boundaries between the different portions. These boundaries are virtual, since the different portions are extensions of one another.

[0146] Fig. 4 represents the two conductive knives 1,2 of the moving contact 20, separated from each other.

[0147] The first knife 1 and the second knife 2 have the same length L, measured parallel to the longitudinal axis D1,D2. The first knife 1 and the second knife 2 have the same width M, measured parallel to the transverse axis T1,T2.

[0148] The first knife 1 and the second knife 2 have the same thickness E, measured parallel to the axis perpendicular to the longitudinal axis D1,D2 and to the transverse axis T1,T2. The thickness E of the conductive knives 1,2 is defined as the thickness at the point of maximum thickness.

[0149] The first knife 1 and the second knife 2 are symmetrical to each other with respect to a plane PI parallel to the first plane Fold defined by the longitudinal axis DI and the transverse axis Tl of the first conducting knife 1.

[0150] The first knife 1 includes a first face 15_1 opposite the second knife 2 in a direction parallel to the axis of rotation R, and the first face 15_1 of the first knife 1 is flat. Similarly, the second knife 2 includes a first face 15_2 opposite the first knife 1 in a direction parallel to the axis of rotation R. The first face 15_2 of the second knife 2 is flat.

[0151] As shown in [Fig.6], the first electrical conductor 19 is arranged between the first face 15_1 of the first knife 1 and the first face 15_2 of the second knife 2, and is in contact with each of these faces under the effect of the force developed by the first elastic element 7.

[0152] Fig. 9 represents the first knife 1, from a different angle of view than that of figures 3 and 4. The second knife 2, not shown, has the same geometric characteristics as the first knife 1, and is symmetrical to the first knife 1.

[0153] Each knife 1.2 comprises two longitudinal edges and two transverse edges. Each knife 1.2 comprises: - a first part 17_1,17_2 of thickness el_1,el_2 less than a predetermined threshold s, the first part 17_1,17_2 extending longitudinally along the longitudinal axis D1,D2 and transversely on either side of the longitudinal axis D1,D2, and - a second part 18_1,18_2 of thickness e2_l,e2_2 greater than the predetermined threshold s, the second part 18_1,18_2 surrounding the first part 17_1,17_2. The second part 18_1,18_2 forms the longitudinal edges of the knife 1,2 and the transverse edges of the knife 1,2.

[0154] Each knife 1,2 is thus formed of a so-called refined portion 17_1, 17_2 extending longitudinally and transversely. This so-called refined portion 17_1, 17_2 is extended by a ridge 18_1, 18_2 of greater thickness than the thickness of the refined portion. The refined portion 17_1, 17_2 is surrounded by the ridge-shaped part 18_1, 18_2.

[0155] The longitudinal edges of each knife 1,2 form part of the second part 18_1,18_2, having an increased thickness. Similarly, the 2 transverse edges are part of the second part 18_1,18_2, having an increased thickness.

[0156] The predetermined threshold s is for example between 30% and 60% of the thickness E of each knife 1,2. The thickness of the second part 18_1,18_2 is equal to the thickness E of each knife 1,2, since this second part 18_1, 18_2 forms respectively the thickest area of ​​the first knife 1 and the second knife 2.

[0157] Fig. 12 illustrates a second embodiment of a knife 1 of the movable contact 20. In this embodiment, each knife 1,2 includes a through recess extending longitudinally along the longitudinal axis D1,D2 and transversely on either side of the longitudinal axis D1,D2. A length LE of the through-hollow is between 20% and 80% of a length L of the knife 1.2. A width ME of the through recess 27_1,27_2 is between 25% and 75% of a width M of the knife 1,2.

[0158] The length LE of the through recess 27_1 is measured parallel to the longitudinal axis Dl of the knife 1. The same applies to the measurement of the length of the through recess of the knife 2. The width ME of the through-cut 27_1 is measured parallel to the transverse axis T1 of the knife 1. Similarly, the width of the through-cut of the knife 2 is measured parallel to the transverse axis T2 of the knife 2.

[0159] In [Fig. 12], the symbol 27_1 designates the through-cut of the knife 1. The second knife 2 is not shown in [Fig. 12]. The second knife 2 is the symmetrical counterpart of the first knife 1, as in the first embodiment.

[0160] The through recess 27_1,27_2 is distant from the longitudinal edges of the knife 1,2 and from the transverse edges of the knife 1,2. In other words, each knife 1,2 is formed from a continuous portion of material surrounding a central through-hollow. In this embodiment, the previously described thinned portion has zero thickness. The central through-hollow forms a material-free zone. The electric current flows in each knife 1,2 in parallel in the portion of material between the first longitudinal edge Bl_l and the through recess 27_1, and in the portion of material between the through recess 27_1 and the second longitudinal edge B2_l. The dimensions LE, ME of the central recess 27_1 are chosen so that the cross-section of the knife has, in the area of ​​the central recess 27_1, a sufficient surface to ensure the passage of a current of an intensity equal to the maximum intensity sought.

[0161] In the example shown, the through recess 27_1 is substantially rectangular in shape. The symbol 28A_1 designates a first portion of electric current flow, and the symbol 28B_1 designates a second portion of electric current flow. The two portions of material 28A_1, 28B_1 separated by the recess traversing 27_1 in a direction parallel to the transverse axis Tl are here of constant thickness. Similarly, the two portions of material 29A_1, 29B_1 separated by the recess traversing 27_1 in a direction parallel to the longitudinal axis DI are of constant thickness. As with the first embodiment, the first longitudinal edge Bl_l and the second longitudinal edge B2_l are rounded in shape.

Claims

Demands

1. A movable contact (20) for an electrical current interruption device (50), comprising: - a first conductive knife (1) and a second conductive knife (2), each conductive knife (1,2) extending longitudinally along a longitudinal axis (Dl, D2), and transversely along a transverse axis (Tl, T2), the longitudinal axis (Dl) and the transverse axis (Tl) of the first conductive knife (1) defining a first plane (Pli), the longitudinal axis (D2) and the transverse axis (T2) of the second conductive knife (2) defining a second plane (P12), the first plane (Pli) and the second plane (P12) being parallel to each other and separated from each other, the first conductive knife (1) and the second conductive knife (2) being rotationally linked about a common axis of rotation (R) perpendicular to the first plane (Pli) and the second plane (P12),- a first spacer (3) and a second spacer (4) arranged between the first knife (1) and the second knife (2), configured to maintain a minimum distance between the first knife (1) and the second knife (2), in which a cross-section (S1,S2) of each knife (1,2) is shaped to: - have an area equal to the area of ​​a reference cross-section (S1',S2') having a rectangular shape and the same length (a), the length (a) being measured parallel to the transverse axis (T1, T2), and - have a second moment of area greater than the second moment of area of ​​the reference cross-section (S1',S2'), the second moment of area being determined with respect to an axis parallel to the transverse axis (T1,T2) of the knives (1,2).

2. A movable contact (20) according to claim 1, wherein each conductive knife (1,2) extends along the transverse axis (Tl, T2) between a first longitudinal edge (Bl_l, Bl_2) and a second longitudinal edge (B2_l, B2_2), wherein a cross-section (S1,S2) of each knife (1,2) comprises: - a first portion (Tl_l, Tl_2) adjacent to the first longitudinal edge (B 1_1, Bl_2) of said knife (1,2), - a second portion (T2_l, T2_2) adjacent to the second longitudinal edge (B2_1,B2_2) of said knife (1,2), - a third portion (T3_1,T3_2) connecting the first portion (T1_1,T1_2) to the second portion (T2_1,T2_2), and in which: - the thickness (e1_l,e1_2) of the first portion (T1_1,T1_2) and the thickness (e2_l,e2_2) of the second portion (T2_1,T2_2) are greater than the thickness (e3_l,e3_2) of the third portion (T3_1,T3_2).

3. Movable contact (20) according to the preceding claim, wherein the thickness (e3_l,e3_2) of the third portion (T3_1,T3_2) is less than 60% of the thickness (el_l,el_2) of the first portion (T1_1,T1_2), preferably less than 50% of the thickness (el_l,el_2) of the first portion (T1_1,T1_2), preferably still less than 40% of the thickness (el_l,el_2) of the first portion (T1_1,T1_2), the thickness being measured parallel to a direction perpendicular to both the longitudinal axis (D1,D2) and the transverse axis (T1,T2).

4. A movable contact (20) according to any one of the preceding claims, comprising: - a first guide bar (5) linked to the first knife (1), extending along an axis (D5) parallel to the axis of rotation (R), configured to allow sliding of the second knife (2) relative to the first knife (1), - a first elastic element (7) configured to apply an elastic force tending to bring the knives (1,2) closer together in a direction parallel to the axis of rotation (R), - a second guide bar (6) linked to the first knife (1), extending along an axis (D6) parallel to the axis of rotation (R), configured to allow sliding of the second knife (2) relative to the first knife (1), - a second elastic element (8) configured to apply an elastic force tending to bring the knives (1,2) closer together in a direction parallel to the axis of rotation (R), in which the first spacer (3) and the second spacer (4) are opposite each other in a direction parallel to the longitudinal axis (D1,D2) of the knives.

5. Movable contact (20) according to any one of the preceding claims in combination with claim 2, wherein the third portion (T3_1,T3_2) of each knife (1,2) extends continuously on either side of the longitudinal axis (D1,D2) of each knife.

6. Movable contact (20) according to any one of the preceding claims in combination with claim 2, wherein the first portion (T1_1,T1_2) and the second portion (T2_1,T2_2) of a cross section (S1,S2) of each knife (1,2) are symmetrical to each other with respect to the longitudinal axis (D1,D2) of said knife (1,2).

7. Movable contact (20) according to any one of the preceding claims in combination with claim 2, wherein the first portion (T1_1,T1_2) of a cross section (S1,S2) of each knife (1,2) comprises a substantially semicircular part, a first longitudinal edge (B1_1,B1_2) of each knife (1,2) forming part of the substantially semicircular part of the first portion (T1_1,T1_2), and wherein the second portion (T2_1,T2_2) of each knife (1,2) comprises a substantially semicircular part, a second longitudinal edge (B2_1,B2_2) of each knife (1,2) forming part of the substantially semicircular part of the second portion (T2_1,T2_2).

8. Mobile contact (20) according to any one of the preceding claims in combination with claim 2, wherein the third portion (T3_1,T3_2) of each knife (1,2) is substantially rectangular in shape.

9. Movable contact (20) according to any one of the preceding claims, wherein the first knife (1) and the second knife (2) are symmetrical to each other with respect to a plane (P) parallel to the first plane (Pli) defined by the longitudinal axis (Dl) and the transverse axis (Tl) of the first conducting knife (1).

10. A movable contact (20) according to any one of the preceding claims, wherein: - the first knife (1) comprises a first face (15_1) opposite the second knife (2) in a direction parallel to the axis of rotation (R), the first face (15_1) of the first knife (1) being flat, and - the second knife (2) includes a first face (15_2) opposite the first knife (1) in a direction parallel to the axis of rotation (R), the first face (15_2) of the second knife (2) being flat.

11. A movable contact (20) according to any one of the preceding claims, wherein each knife (1,2) comprises two longitudinal edges and two transverse edges, and wherein each knife (1,2) comprises: - a first portion (17_1,17_2) of thickness (e1_1,e2) less than a predetermined threshold (s), the first portion (17_1,17_2) extending longitudinally along the longitudinal axis (D1,D2) and transversely on either side of the longitudinal axis (D1,D2), and - a second portion (18_1,18_2) of thickness (e2_1,e2_2) greater than the predetermined threshold (s), the second portion (18_1,18_2) surrounding the first portion (17_1,17_2), the second portion (18_1,18_2) forming the longitudinal edges of the knife (1,2) and the transverse edges of the knife (1,2).

12. Movable contact (20) according to any one of the preceding claims, wherein each knife (1,2) comprises: - a through recess (27_1,27_2) extending longitudinally along the longitudinal axis (D1,D2) and transversely on either side of the longitudinal axis (D1,D2), a length of the recess (27_1,27_2) being between 20% and 80% of a length of the knife (1,2), a width of the recess (27_1,27_2) being between 25% and 75% of a width of the knife (1,2).

13. An electrical current interruption device (50), comprising: - a first portion of an electrical line (25-1) comprising a first electrical conductor (19) and a movable contact (20) according to any one of the preceding claims, the contact (20) being rotatable relative to the first electrical conductor (19), - a second portion of an electrical line (25-2) comprising a second electrical conductor (22) and a fixed contact (21) integral with the second electrical conductor (22), the movable contact (20) being configured to be moved between: - a first position (PI) called the opening position in which the moving contact (20) is separated from the fixed contact (21) so as to prohibit the passage of electric current between the first portion of the electric line (25-1) and the second portion of the electric line (25-2), and - a second position (P2) called the closing position in which the moving contact (20) is in contact with the fixed contact (21) so as to allow a passage of electric current between the first portion of the electric line (25-1) and the second portion of the electric line (25-2).

14. Medium voltage electrical apparatus (100), configured to selectively make or break the current in a medium voltage electrical network comprising three phases (Phl,Ph2,Ph3), comprising an electrical current interruption device (50A, 50B, 50C) according to the preceding claim disposed respectively on each of the phases (Phl,Ph2,Ph3) of the electrical network.

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