FR2694838A1 - Transmission line circuit breaker confining build-up of arcing - has isolator contacts in air in form of tapered strip and clip with two side flanges separated by cylindrical conducting rod - Google Patents

Abstract

The circuit breaker includes the contact strip (52) and the contact clip (54) which are interchangeable as fixed and moving contacts. The rod between the side flanges (60, 62) confines the discharge to the tapered end of the strip and the rod. The circuit breaker is in a controlled atmosphere (100) and is disconnected by a control mechanism (150) passing an equilibrium point. A conducting opening lever (195) rotates the control mechanism and joins with one of the isolator contacts to ensure a current flows across the circuit breaker. A guide (196) maintains the contact from the start of opening the circuit breaker and the push of a spring on the lever after passing the equilibrium point extends the contact time. ADVANTAGE - Actual contacts are free from degradation due to arcing.

Description

 The present invention relates to the field of switching devices for power lines.

 More specifically, the present invention relates to a cut-off device for an electrical line of the known type comprising a disconnector comprising a fixed contact and a movable contact in which one of the contacts is formed by a blade or knife while the other contact is formed of a clamp comprising two lateral flanges capable of enclosing said blade.

 Many cut-off devices of the aforementioned type have already been proposed.

 The present invention applies in particular, but not exclusively to cut-off devices for electric lines comprising a disconnector in 1 r air associated with a switch under controlled atmosphere.

 Numerous breaking devices have already been proposed associating a disconnector in the air and a switch under controlled atmosphere. Generally the disconnector in the air and the switch under controlled atmosphere each comprise a fixed contact and a movable contact.

 In addition, these known breaking devices most often include a control mechanism which includes a spring energy accumulator, with exceeding of equilibrium point, to control the opening and closing of the switch in a controlled atmosphere.

 The known cut-off devices of the aforementioned type, comprising a disconnector in the air and a switch under controlled atmosphere have given rise to an abundant literature. Examples include FR-A1435209, FR-A-2485252, FR-A-2529712, FR-A-1580713, DE-A1156141, DE-A-2522525, DE-A-2819019, DE-A-2103600 , US-A3769478, US-A-3566055, US-A-3824359, US-A-3171004, US-A3032632 and US-A-2769063.

 The Applicant has already proposed improvements to the known cut-off devices with disconnector in the air and switch under controlled atmosphere, in its French patent application filed on April 26, 1991 under N091 05176.

 The present invention now aims to propose new improvements to known breaking devices.

 According to the present invention, this object is achieved by means of an electrical line cut-off device of the known type described above comprising a disconnector comprising a fixed contact and a movable contact in which one of the contacts is formed by a blade or knife while that the other contact is formed by a clamp comprising two lateral flanges capable of enclosing said blade, characterized in that the free end of the blade is tapered and the device comprises an electrically conductive bar placed between the two flanges of the clamp to confine any initiation of electrical discharge, during the switching of the disconnector, between said tapered tip of the blade and the electrically conductive bar.

 According to another characteristic of the present invention, the electrical line cut-off device comprises a disconnector in the air, a switch under controlled atmosphere and a control mechanism which comprises a spring energy accumulator, with point overflow. balance, to control the opening and closing of the switch in a controlled atmosphere, and this device is characterized by the fact that it comprises an opening lever made of electrically conductive material which pivots the control mechanism and which cooperates with one of the switch contacts to ensure the passage of current through the switch under controlled atmosphere, in which one of the lever and of said switch contact is provided with a guide adapted to maintain an electrical connection between the lever and the disconnector contact, during an opening phase of the switch under controlled atmosphere, as long as the latter is not have opened.

 According to another advantageous characteristic of the present invention, the driving of the opening lever by the spring of the control mechanism, after crossing the equilibrium point, makes it possible to lengthen the intercontact between said contact of the disconnector and the guide of the opening lever.

 According to another advantageous characteristic of the present invention, the other of the lever and of the disconnector contact comprises an auxiliary contact formed by a rod of electrically conductive material engaged in the guide.

 According to another advantageous characteristic of the present invention, the guide comprises at least one U-shaped slide.

 According to another advantageous characteristic of the present invention, the device comprises two opening levers each provided with a guide formed by a U-shaped slide.

 Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows, and with reference to the appended drawings given by way of nonlimiting example and in which - FIG. 1 represents a schematic side view of a cut-off device according to the present invention, in solid lines in the closed position, and in dotted lines in the open position, - Figure 2 shows a perspective view, and in the closed position, of the same cut-off device , - Figure 3 shows a partial perspective view of the same cut-off device, during an intermediate phase of the opening process, - Figure 4 shows another partial perspective view of the same cut-off device, during a intermediate phase of the closing process, - Figure 5 shows an end view of an auxiliary contact according to the present invention linked to the movable contact of the disconnector d in air, - Figure 6 shows a schematic view in longitudinal axial section of a switch under controlled atmosphere and its associated control mechanism - Figure 7 shows an alternative embodiment according to which the breaking device only comprises a disconnector in the air, - Figure 8 shows an alternative embodiment of the device illustrated in Figure 1, - Figure 9 shows a side view of a flange of a movable contact clamp of a variant embodiment to the present invention, equipped with a flexible whisk, - Figure 10 shows a view of the same part, seen from above, - Figure 11 shows an end view of the flange, - Figure 12 shows a side view of 'a fixed contact blade according to the same alternative embodiment of the present invention, equipped with a hook designed to cooperate with the aforementioned whip, and - Figure 13 shows a top view of the same blade .

 The breaking device according to the present invention shown in the appended figures has a general symmetry with respect to a median plane parallel to the plane of FIG. 1.

 In the appended FIG. 1, it is seen a cut-off device for an electric line according to the present invention which comprises an air disconnector 50 and a switch under controlled atmosphere 100.

 This cutting device comprises a frame 10 preferably designed to be fixed at the top of a post.

However, the cut-off device can be installed elsewhere, for example on one face of the post or in a cover placed on the ground or buried. Each cut-off device being adapted to cut a single electric line, this chassis 10 supports a number of cut-off devices equal to the number of electric lines to be cut, preferably three cut-off devices.

However, to simplify the illustration, a single switching device is shown in the attached figures.

 The other switching devices are preferably identical to that shown in the appended figures.

 The cut-off device shown comprises three insulators 12, 14, 20. The two lateral insulators 12, 14 are fixed on the frame 10. They are preferably vertical. The fixed insulators 12, 14 support on their head 13, 15 pins 16, 17 of electrically conductive material, adapted to be connected by any known means suitable for respective sections of the power line to be cut.

 The central insulator 20 is pivotally mounted, at its base 21, on the chassis 10, around a horizontal axis 22.

 The air disconnector 50 comprises a fixed contact 52 and a movable contact 54. The fixed contact 52 is linked to the head 13 of the fixed lateral insulator 12.

 The movable contact 54 is placed at the first end of a straight rod 56 articulated by its second end, around a horizontal axis 58, on the head 15 of the lateral insulator 14. The axis 58 is parallel to the axis 22 above.

 The fixed contact 52 is permanently connected to the pin 16. Similarly, the movable contact 54 is connected via the rod 56, made of electrically conductive material, to the pin 17.

 The rod 56 is formed by a rectilinear slide open downwards towards the pivoting central insulator 20. This insulator 20 carries at its head 23 a roller 24 articulated around a horizontal axis and engaged in the slide formed by the rod 56. The axis 24 is parallel to the aforementioned axes 22 and 58.

 Those skilled in the art will understand that thanks to the cooperation defined between the roller 24 and the slide 56, any pivoting of the central insulator 20 around the axis 22, results in a pivoting of the rod 56, and consequently of the movable contact 54, around the horizontal axis 58.

 Thus, the pivoting of the central insulator 20 around the axis 22 makes it possible to move the movable contact 54 between a first position shown in solid lines in FIG. 1 in which the movable contact 54 is supported on the fixed contact 52, the disconnector in the air is then closed, and a second position shown in broken lines in FIG. 1 in which the movable contact 54 is separated from the fixed contact 52, the disconnector in the air is then opened.

 More precisely, according to the particular embodiment shown in FIG. 1, the fixed contact 52 is formed by a blade or knife comprising at least one generally vertical plane section which cooperates with the movable contact 54.

 This movable contact 54 is preferably formed of a clamp composed of two flanges or parallel lateral cheeks 60, 62 visible in particular in FIG. 5, able to grip the blade - fixed 52. To facilitate engagement of the clamp of the contact movable 54 on the knife of the fixed contact 52, preferably the two cheeks 60, 62 have respective lower engagement edges 61, 63 which diverge as can be seen in FIG. 5.

 Of course, provision can be made to reverse the arrangement of the contact structures which have just been described. That is to say that one can provide a fixed contact 52 formed of a clamp comprising two parallel lateral cheeks as shown in FIG. 5, while the movable contact 54 would then be formed of a knife similar to the blade shown in FIG. 1 under the reference 52.

 The controlled atmosphere switch 100 is fixed to the head 13 of the insulator 12. It can be the subject of a large number of embodiments. It can be a switch comprising a vacuum bulb, or even a bulb filled with a neutral gas, for example SF6.

 These switches under controlled atmosphere are well known to those skilled in the art and will therefore not be described in detail below. If necessary, reference may also be made to the documents of the prior art cited above.

 Generally, these controlled atmosphere switches include a fixed contact and a movable contact. This movable contact is guided in translation relative to the fixed contact, between an open position and a closed position on the latter, along the axis of the bulb.

 In FIG. 6, 102 has thus been referenced the casing of the vacuum interrupter, 104 the fixed contact and 106 the movable contact. The contacts 104, 106 are formed from coaxial cylindrical rods made of electrically conductive material, for example an alloy of copper centered on the axis 107 of the bulb. The bulb 102 is closed at its ends by two sealed flanges 108, 110. The rods 104, 106 pass through these flanges 108, 110. The movable rod 106 is guided in translation along the axis 107 at the flange 110 by a guide 112. The casing 102 also houses two annular deflectors 114, 116 serving as a breaking chamber, formed of skirts of electrically conductive material. The deflector 114 is carried by the flange 108. On the other hand, the deflector 116 is connected to the flange 110.

 In Figure 6, the controlled atmosphere switch is shown in the open position, the contacts 104, 106 being separated.

 Preferably, the switch 102 is placed in an external envelope 120 for protection against the weather. Preferably, the external envelope 120 comprises a tube 122 of electrically insulating material, for example of polyacetal, covered with an external sheath 124, preferably of elastomeric material. The sheath 124 can be placed on the tube 122 by overmolding. As a variant, the sheath 124 can be heat-shrinkable. Preferably, and in a manner known per se, the outer sheath 124 is provided with frustoconical fins 125 intended to lengthen the line of flight on the outside.

 The fixed contact 104 emerges at the lower end of the switch 100. It is permanently connected to the pin 16, and therefore to the fixed contact 52.

 The movable contact 106 emerges at the upper end of the switch 100.

 The controlled atmosphere switch 100 is actuated by a control mechanism 150.

 The mechanism 150 is placed in the upper part of the switch under controlled atmosphere 100. The mechanism 150 is a triggering mechanism comprising a spring energy accumulator, with exceeding of equilibrium point, for actuating the movable contact 106 of the 'light switch.

 The mechanism 150 can be the subject of numerous embodiments.

 According to the preferred embodiment shown in the appended figures, in particular in FIG. 6, this mechanism 150 comprises a housing 151, two parts 160, 170 and a spring 180.

 The two parts 160, 170 are rigid parts articulated around a common axis 152. The axis 152 is fixed relative to the housing 151. The axis 152 is parallel to the above-mentioned horizontal axes 22, 24 and 58. The axis 152 is materialized by a pin 153.

 The first part 160 is mounted on the pin 153, free to rotate relative to the latter.

 Furthermore, the part 160 is articulated around an axis 162 on a part 164 fixed on the end of the movable contact rod 106 external to the bulb 102 of the switch 100. The axis 162 is a horizontal axis parallel to the above-mentioned axis 152. The axis 162 is distinct from the axis 152. The axis 162 is at least substantially coplanar with the axis 107 of translation of the movable contact rod 106. The plane defined by the axes 152 and 162 is generally transverse to l axis 107 of translation of the movable contact 106.

 Those skilled in the art will readily understand that the pivoting of the part 160 around the axis 152 causes a translational movement of the movable contact rod 106.

However, the rotation of the part 160 around the axis 152 causes a displacement of the axis 162 on an arc centered on the axis 152. To allow this displacement of the axis 162, a flexible connection can be provided between the part 160 and the movable contact rod 106, at the level of the part 164.We can also provide for placing the pin materializing the axis 162 in a lumen formed on the part 164 and transverse to the axis 107 of movement of the mobile contact 106.

 The second part 170 is mounted on the pin 153 and linked in rotation with the latter.

 The rotational connection between the part 170 and the pin 153 can be obtained using any suitable conventional means. Preferably, the part 170 comprises a structure in the form of a yoke 172 engaged on a complementary structure, not symmetrical in revolution, formed on the pin 153.

 The spring 180 is a helical tension spring. A first end 181 of the spring 180 is fixed on the part 170. More specifically, the end 181 of the spring 180 is fixed on the end 174 of the part 170 opposite the pin 153 and therefore the axis 152. The second end 182 of the spring 180 is fixed on the part 160. More precisely, the second end 182 of the spring 180 is fixed on the part 160 between the axis 152 and the axis 162. Preferably, the axis 152, the axis 162 and the center of attachment of the end 182 of the spring 180 are coplanar.

 FIG. 6 shows the mechanism 150 for controlling the switch 100 in the open position.

 In this position the two attachment points 181, 182 of the spring 180, respectively on the part 170 and on the part 160, are placed on the same side of the hinge pin 152, ie opposite the 'switch 100.

The system is stable. The spring 180 exerts on the movable rod 106 of the switch a force directed towards the outside of the latter, which moves the movable rod 106 away from the fixed rod 104.

 To place the switch 100 in the closed position, the part 170 must be rotated about the axis 152, in the counterclockwise direction according to the representation given in FIG. 6.

 For this, the pin 153 crosses the housing 151 and is connected to the outside of the latter, respectively at its two ends, to two cylindrical mounts 176, centered on the axis 153, which each carry an opening lever 195 and a closing lever 190.

 There are thus provided two opening levers 195 and two closing levers 190 respectively on each side of the control device 150.

 The opening 195 and closing 190 levers are preferably rectilinear and generally radial with respect to the axis 152. The inclination between each opening lever 195 and the associated closing lever 190 is typically twisted by 300.

 The opening levers 195 are made of electrically conductive material.

 The closing levers 190 can also be made of electrically conductive material. They can also be made of electrically insulating material to prevent the bulb 100 from being at potential when the device is closed.

 The opening levers 195 are placed above the closing levers 190.

 The levers 195, 190 are pivotally driven around the axis 152, to move the part 170 and control the switch 100 accordingly, by an auxiliary contact 70 linked to the movable contact 54. The auxiliary contact 70 can be the object many embodiments. Preferably, it is formed of a rod of electrically conductive material, for example copper, rectilinear and fixed to the cheeks 60, 62 of the movable contact 54, perpendicular thereto. The rod 70 emerges on either side of the side cheeks 60, 62, as can be seen in FIG. 5, to cooperate with the levers 195, 190, these being placed on the outside of the cheeks 60, 62, as shown in Figures 2, 3 and 4 in particular.

 The pivoting of the levers 195, 190 and consequently of the part 170, is therefore obtained by the pivoting of the central insulator 20 which itself displaces the rod 56.

 When the part 170 is pivoted, the spring 180 is tensioned, since the pivoting of the part 170 around the axis 152 leads to an increase in the distance between the two ends 181, 182 of the spring 180.

 During its pivoting, the part -170 reaches an unstable position in which the two attachment points 181, 182 of the spring 180 are coplanar with the articulation axis 152. The parts 160, 170 are then diametrically opposite with respect to to axis 152. The unstable position thus obtained corresponds to a position called equilibrium point in the context of the present patent application.

 Those skilled in the art will readily understand that as soon as the attachment point 181 of the spring 180 on the part 170 crosses the plane defined by the axis 152 and the second attachment point 182 of the spring 180, the part 160 switches over rapidly approaching the switch 100 to switch the latter to the closed position. Indeed, the direction of the force exerted by the spring 180 on the articulated part 160 and the contact rod 106 is then no longer directed away from the fixed contact rod 104. this effect is directed towards this rod 104, from the fact that the two attachment points 181, 182 of the spring 180 are then placed on the other side of the axis 152, namely that which is adjacent to the switch 100. Crossing the point of equilibrium causes rapid movement of the movable contact 106.

 It can be noted that thus the spring 180 is not maintained under maximum traction permanently. The energy stored in the spring 180 to cause a sudden pivoting of the part 160 and a rapid switching of the switch 100r is only generated during the pivoting of the part 170. However, the spring remains at least slightly under tension, in the two extreme rest positions of the mechanism 150, to permanently urge the movable contact 106 respectively in the open position and in the closed position.

 Those skilled in the art will readily understand on examining the mechanism 150 shown in FIG. 6 that the position of the point of equilibrium in the direction of opening is offset from the position of the point of equilibrium in the direction of closure. In both cases, the point of equilibrium is reached when the part 170 is diametrically opposite to the part 160. This offset between the position of the equilibrium point at closing and the position of the equilibrium point at opening generates a hysteresis effect. In Figure 6 we have sketched in broken lines under the reference 160a the position occupied by the part 160 in the closed position of the switch 100. The two points of balance are therefore achieved when the part 170 is respectively aligned with the two positions of the part 160 shown in FIG. 6 in solid lines and in broken lines.

 As indicated previously, according to the present invention, the opening levers 195 are each provided at their free end opposite the mechanism 150, with a guide 196 cooperating with the auxiliary contact 70 to guarantee an electrical connection between the levers 195 and the contact auxiliary 70, or therefore with the movable contact 54, as long as the switch 100 is not switched to the open position.

 Guides 196 are made of electrically conductive material.

 More specifically, preferably a guide 196 is provided at the end of each opening lever 195.

 Each guide 196 comprises, as can be seen in particular in FIGS. 2, 3 and 4, a U-shaped slide or angle oriented parallel to the opening levers 195 and open in the direction of the side cheeks 60, 62 of the fixed contact 54 for receiving the moon of the ends of the auxiliary contact 70. The slides 196 are thus open respectively opposite one another.

 Even more preferably, each slide 196 is formed of an outer core 1960 and two wings 1962, 1964 parallel to each other and orthogonal to the base 1960. The width of the slide 196, that is to say the distance separating the wings 1962 and 1964 must be greater than the diameter of the bar 70. Furthermore the length of the slide must be adapted to guarantee electrical contact between this slide and the bar 70, from the engagement of the bar 70 in the slide is practically from the initiation of the opening movement, and until after the effective opening of the switch 100.

 The engagement edges of the lower wings 1962, that is to say the edges of these wings 1962 closest to the mechanism 150, are preferably curved and diverge away from the upper wings 1964 to facilitate the engagement of the bar 70 in the slides 196.

 The slides 196 can be fixed by any suitable conventional means to the levers 195, for example by welding or bolting.

 Those skilled in the art will understand that during the process of opening the device, the bar 70 moves along the slides 196.

 As indicated above, according to the present invention, the blade 52 forming the fixed contact is tapered at its free end 53, that is to say its end engaged first between the cheeks 60, 62 of the movable contact 54, while a bar 75 of electrically conductive material, for example copper, is fixed between the two cheeks 60, 62, perpendicular to the latter. The bar 75 is advantageously cylindrical of revolution. The bar 75 can be merged with the aforementioned bar 70, as shown in the attached figures.

 The position of the bar 75 between the cheeks 60, 62 is adapted so that this bar 75 is placed substantially opposite the tapered end 53 of the blade 52, during the process of closing the disconnector. To this end the distance separating the external generator of the bar 75 and the axis 58 is advantageously substantially equal to the distance separating the axis 58 and the external face of the knife 52.

 This arrangement, tapered blade 52 and presence of the electrically conductive bar 75, improves the reliability of the system.

 In fact, the Applicant has observed significant sparking, during the closing process, in particular during closing on a short circuit, between cheeks of movable contacts in the form of pliers and fixed knives, on conventional cut-off devices. This sparking leads to a degradation of the cheeks of the mobile contacts and sometimes a bonding of the fixed contacts on the mobile contacts.

 The part 75 added according to the invention to these known devices allows confining a pre-ignition of the electric arc between the tip 53 of the fixed blade 52 and said part 75. It avoids any electric arc between the cheeks 60, 62 of the movable contact 54 and the sides of the fixed contact 52. It thus avoids any degradation of the fixed contacts 52 and movable 54, at their active surfaces in the closed position of the disconnector (cheeks 60 and 62 and sides of the knife 52). The closing of the disconnector is thus carried out without problem and without risk of sticking of the contacts 52 and 54 of the disconnector. The operating torque for opening the disconnector is therefore low and constant.

 If necessary, the electric arc generated between the bar 75 and the tip 53 of the fixed contact 52 may cause slight degradation of these. However, this degradation is immaterial insofar as the degraded portions of the bar 75 and the tip 53 of the fixed contact 52 are inactive on the electrical plane in the closed position of the disconnector. The diameter of the bar 75 can be adjusted as a function of the intensity of the short circuit.

 The general operation of the system which has just been described is as follows.

 In the closed position, the elements occupy the position shown in solid lines in FIG. 1.

The roller 24 is placed at the end of the slide 56 adjacent to the movable contact 54. This movable contact 54 is engaged on the fixed contact 52. The disconnector 50 is therefore closed. The two levers 190, 195 of each pair are placed respectively on either side of the auxiliary contact 70, at a distance from the latter. The switch 100 is also in the closed position.

 When the insulator 20 is pivotally driven about the horizontal axis 22, the roller 24 rolls in the slide 56. The latter is pivotally driven, clockwise according to the representation given in the figure 1, around the axis 58. The auxiliary contact 70 then abuts against the opening levers 195 to drive these and the associated part 170 around the axis 152. The auxiliary contact 70 then engages in the guides 196 and moves along them.

 In an intermediate phase of the pivoting of the central insulator 20, the movable contact 54 separates from the fixed contact 52. This separation between movable contact 54 / fixed contact 52 is obtained before the opening of the switch 100 and before separation of the auxiliary contact 70 and levers 195, thanks to the guides 196, as shown in FIG. 3. At this stage, the current flows through the switch 100, the opening levers 195, the auxiliary contact 70, and the rod 56.

 In a later phase of the pivoting of the central insulator 20, and consequently of the levers 195, the switch under controlled atmosphere 100 is suddenly controlled upon opening, when the point of equilibrium is crossed by the mechanism 150.

 It will be noted that the driving of the opening levers 195 by the spring 180 of this mechanism 150 after crossing the point of equilibrium by the part 170, makes it possible to lengthen the inter-contact between the movable contact 54 and the guides 196 opening levers 195.

 The device is shown in broken lines in the open position, in FIG. 1.

 In the open position, the roller 24 is placed at the end of the slide 56 adjacent to the axis 58.

 To close the breaking device, the central insulator 20 is pivoted in the opposite direction around the axis 22, that is to say in the anticlockwise direction according to the representation given in FIG. 1.

 Initially, the auxiliary contact 70 comes to rest against the closing levers 190, as shown in FIG. 4. Subsequently, the pivoting of the rod 56 consequently drives the mechanism 150, and more particularly the part 170. The The switch 100 is closed when the new equilibrium point is crossed.

 Thanks to the hysteresis obtained at the level of the control mechanism 150, it is possible to ensure the closing of the disconnector 50, that is to say the establishment of the contact between the elements 52, 54, before the closing of the switch 100.

 Preferably, there is provided according to the present invention a clearance in the connection established between the part 160 of the mechanism 150 and the movable contact rod 106, to allow the initial launching of said part 160 without acting on the contact 106. More precisely the clearance thus defined is an axial clearance, oriented along the axis of translation of the movable contact of the switch. The contact 106 is only driven after crossing this clearance, that is to say after the part 160 has reached an initial non-zero speed making it possible to move the movable contact of the switch in the speed range imposed by the vacuum cutting technology. In addition, this arrangement guarantees good synchronism between the different cut-off devices.

The Applicant has also established that this arrangement is advantageous for guaranteeing the opening of the switch 100 in the event of accidental prior bonding between the contacts 104, 106. Preferably, the clearance J is adapted to allow the part 160 to acquire a minimum speed of 0.5 m / s before driving contact 106.

 In addition, the Applicant has established that it was preferable to isolate the spring 180, electrically, to avoid any passage of current through it and therefore any modification of the characteristics of the latter, by annealing, in the event of current. important. For this, it suffices to place an electrically insulating part in series with the mechanism 150. Of course, the mechanism 150 must then be electrically shunted, for example using a metal braid, to ensure a permanent electrical connection between the movable contact 106 and opening levers 195.

 Of course the present invention is not limited to the particular embodiment which has just been described but extends to any variant in accordance with its spirit.

 In particular, provision may be made to place the switch 100 associated with the control mechanism 150, with the opening lever 195 and closing lever 190 not in parallel with the fixed contact 52, but in series with one of the contacts of the disconnector 50 , either in series with the fixed contact 52 or in series with the movable contact 54.

 Furthermore, it is possible to envisage reversing the auxiliary contact arrangement 70 / guides 196, by placing the auxiliary contact 70 on the opening levers 195 and by placing complementary guides 196 on the movable contact 54.

 Preferably, means are further provided for adjusting the angular position of the levers 195, 190 relative to the axis 152.

 To this end we see in Figure 1 attached, circular lights 177 centered on the axis 152, formed in the mounts 176, to adjust the angular position between the mounts 176 linked to the levers 195 and 190, and the pin 153 .

 Furthermore, the present invention is not limited to the general structure of the switching device shown in the appended figures. It extends to a large number of variants.

 As indicated previously, the present invention is not limited to breaking devices comprising a controlled atmosphere switch associated with a disconnector in the air. It also applies to breaking devices comprising only a disconnector in the air, without including a controlled atmosphere switch, as shown in Figure 7 attached.

 In addition, the slide 56 can be split into two arms 560, 562 articulated together around an axis 564, one 562 articulated around the axis 58 on the insulator 14 and the other 560 articulated on the head 23 of the insulator 20, the roller 24 then being removed, as described for example in the French patent application in the name of the applicant N "91 05176 and as shown in Figure 7 attached.

 FIG. 8 shows an alternative embodiment according to which the opening arm 195 and the closing arm 190 provided respectively on each side of the mechanism 150 are formed of a plate 1900 of electrically conductive material, in the form of " V ". I1 is thus provided two vertical plates 1900 in "V" respectively on each side of the mechanism 150. In addition these two plates 1900 are joined by an upper element 1902 generally horizontal, of electrically insulating material. The element 1902 serves to protect against avifauna, to mechanically fix the plates 1900, and to protect contacts 52, 54 against the ice.

 It will also be noted that according to FIG. 8, the chassis 10 is formed of two telescopic elements 1000, 1002 which can be moved horizontally, capable of being fixed in the position chosen by means 1004. One of the elements 1000 carries the insulators 14 and 20. The other element 1002 carries the insulator 12 and the fixed contact of the disconnector. The device is thus modular. The element 1002 equipped with the insulator 12 is interchangeable. This arrangement is advantageous when the switch is removed and a whip is used, as is known to those skilled in the art.

 We will now describe the alternative embodiment of the movable contact 54 in the form of a clamp and of the fixed contact 52 in the form of a blade shown in FIGS. 9 to 13 appended.

 This variant embodiment shown in FIGS. 9 to 13 comprises a flexible whip 200 associated with a hook 300.

 The use of such a combination of a whip and a hook is well known to those skilled in the art. It improves the breaking capacity of the disconnectors.

 Such a whip and hook system is described for example in documents FR-A-1534114 and FR-A-2495822.

 The whip 200 and the hook 300 are placed respectively on the movable contact 54 and the fixed contact 52. In the closed position of the disconnector, the whip 200 is engaged with the hook 300. Thus, when the contacts 52 and 54 separate, the current continues to pass temporarily through the whip 200 and the hook 300 to avoid the creation of an arc.

 When the movable contact of the disconnector arrives at a sufficient distance from the fixed contact, the whip 200 is released from the hook 300 in a brutal and rapid manner, which allows the extinguishing arc to be extinguished by lengthening the latter in non-ionized air.

 To this end, as shown in FIGS. 9 to 10, the flexible whip 200 is fixed by its base 210 on an axis 212, parallel to the bar 75, and fixed between the flanges 60, 62.

 The hook 300 is fixed to one of the main surfaces of the fixed contact 52.

 Furthermore, and it is in this that the variant shown in FIGS. 9 and 10 differs essentially from that previously described, the bar 75 visible in FIG. 10 extends over only part of the distance separating the two. flanges 60, 62, to allow the whip 200 to pass between the flanges 60, 62.

 According to FIG. 10, the bar 75 is thus fixed on the flange 60. I1 extends substantially over 2/3 of the distance separating the two flanges 60 and 62. The width of the free space between the flange 62 and l the free end of the bar 75 must be greater than the diameter of the whip 200.

 More specifically, preferably, the whip 200 is composed of a base 210 fixed to a flexible and elastic rod 220, by means of a ferrule 230.

 More precisely still, preferably, the base 210 is shaped as an elastic spiral 214 wound around the axis 212. The free end of the spiral 214 which is opposite the whip 200 is fixed on the axis 212 or on the adjacent flange 60. Thus the whip 200 placed on an axial end of the spiral 210 is adjacent to the flange 62, facing the free passage formed between the flange 62 and the bar 75.

 In Figures 9 and 10 attached, the flexible rod 220 of the whip is only partially shown.

 The flexible rod 220 can be made from material sold under the brand ZYCRAL, while the spiral base 214 is made from spring steel. This arrangement makes it possible to produce the flexible rod 220 in a material of low weight and therefore to limit the inertia of the whip 200.

 Note that to improve the elasticity of the contact clip 54, the flanges 60 and 62 are advantageously each provided with a longitudinal slot 80 which opens on its free front edge 82. The slot 80 typically extends over half of the length of the flanges 60, 62. Conventionally, to avoid any accidental extension of the slots 80, these open, opposite the free edge 82, in a flared cut 84. Preferably, the free edges 86, 87 slots 80 are inclined towards the outside of the clamp 54 to avoid any interference with the blade 52 during the maneuvers.

 According to the embodiment shown in FIGS. 12 and 13, the hook 300 is fixed by a screw 302 / nut 304 system, on the fixed blade 52.

 The hook 300 can be the subject of different variant embodiments.

 According to the particular embodiment shown in Figures 12 and 13, the hook 300 comprises a straight main section 310, which extends parallel to the blade 52. The section 310 is extended on one side by a secondary section 320, also straight, which is inclined, for example by about 30, relative to the main section 310. The main section 310 and the secondary section 320 thus form the hook in which the whip 200 is hooked, in the disconnector closed position .

 On the other side, the main section 310 is extended by a semi-cylindrical loop 330. This is centered on an axis 332 parallel to the surface of the blade 52. The loop 330 itself extends by a U-shaped pin 334 with two branches 336, 337 by which the whip 300 is fixed to the blade 52 by the screw 302 / nut 304 system, thanks to an intermediate plate 306.

 Preferably to reinforce the immobilization of the whip 300 on the blade 52, there are provided bosses which serve as support for the branches 336, 337 of the pin 334. According to FIG. 13, there is thus provided a pin 340 placed between the two branches 336, 337 of the pin 334 and a pair of bosses 341, 342 which frame the moon 336 of the two branches of the pin 334.

 It is understood that according to the embodiment shown in Figures 9 to 13 and previously described, the hook 300 is centered in the axis of the main contact, between the flanges 60, 62. However, the whip 200 is off-center.

 When closing, the whip 200 must snap into the hook 300. For this, provision is preferably made for the whip 200 to be placed substantially opposite the secondary section 320 of the hook, generally at mid-length thereof. .

 Furthermore, the main contact blade 52 must be adapted so as not to hinder the movement of the whip 200.

 It is however possible, as a variant, to center the whip 200 between the flanges 60, 62, subject to offsetting the hook 300 accordingly and adapting the fixed blade 52 so that the latter does not interfere with the operations of the whip 200.

Claims (31)

 1. An electrical line cut-off device of the known type comprising a disconnector comprising a fixed contact (52) and a movable contact (54) in which one of the contacts is formed by a blade or knife (52) while the another contact is formed by a clamp comprising two lateral flanges (60, 62) able to grip said blade (52) characterized in that the free end of the blade (52) is tapered and the device comprises an electrically conductive bar (75) placed between the two flanges (60, 62) of the clamp to confine any initiation of electrical discharge, during the switching of the disconnector, between said tapered tip of the blade (52) and the electrically conductive bar (75).  2. Device according to claim 1, characterized in that the bar (75) is cylindrical in revolution.  3. Device according to one of claims 1 or 2, characterized in that the knife (52) is fixed, while the clamp (54) is movable.  4. Device according to one of claims 1 or 2, characterized in that the knife (52) is movable, while the clamp (54) is fixed.  5. Device according to one of claims 1 to 4 of the type comprising an air disconnector (50), a controlled atmosphere switch (100) and a control mechanism (150) which comprises a spring energy accumulator (180), with exceeding of equilibrium point, for controlling the opening and closing of the switch under controlled atmosphere (100), characterized in that it comprises an opening lever (195) made of electrically material conductor which pivotally actuates the control mechanism (150) and which cooperates with one of the contacts of the disconnector (54) to ensure the passage of the current passing through the switch under controlled atmosphere (100), characterized in that the '' of one of the lever (195) and of said switch contact (54) is provided with a guide (196) adapted to maintain an electrical connection between the lever (195) and said switch contact, during an opening phase of the switch under controlled atmosphere ée (100), as long as the latter is not open.  6. Device according to claim 5, characterized in that the drive of the opening lever (195) by the spring (180) of the control mechanism (150), after crossing the equilibrium point, makes it possible to lengthen the intercontact between said contact of the disconnector (54) and the guide (196) of the opening lever (195).  7. Device according to one of claims 5 or 6, characterized in that the other of the opening lever (195) and of the contact (54) of the disconnector comprises an auxiliary contact (70) formed of a rod in electrically conductive material capable of entering the guide (196).  8. Device according to one of claims 5 to 7, characterized in that the guide (196) comprises at least one U-shaped slide.  9. Device according to one of claims 5 to 8, characterized in that it comprises two opening levers (195) each provided with a guide (196) formed of a U-shaped slide.  10. Device according to one of claims 5 to 9, characterized in that each slide (196) extends parallel to the opening lever (195) associated.  11. Device according to one of claims 5 to 10, characterized in that the guide (196) is placed at the end of the opening lever (195) while the associated contact of the disconnector (54) comprises a contact auxiliary (70) able to penetrate the guide (196).  12. Device according to one of claims 5 to 10, characterized in that the guide (196) is placed on said contact of the disconnector (54) while the end of the opening lever (195) is provided with an auxiliary contact (70) able to penetrate the guide (196).  13. Device according to one of claims 5 to 12, characterized in that it further comprises at least one closing lever (190) for the control mechanism (150).  14. Device according to one of claims 5 to 13, characterized in that each lever (195, 190) is generally rectilinear and radial relative to the pivot axis of the control mechanism (150).  15. Device according to one of claims 1 to 14, characterized in that it comprises three insulators (12, 14, 20), including two fixed insulators (12, 14) which carry pins for connection to sections of line to be cut and a pivoting isolator (20) for the command to open and close the disconnector.  16. Device according to one of claims 5 to 15, characterized in that the control mechanism (150) comprises a housing (151), two rigid parts (160, 170) articulated around a common axis (153) and a spring (180) fixed on the two parts (160, 170) respectively on either side of the axis (153).  17. Device according to one of claims 5 to 16, characterized in that a clearance is provided in the mechanical connection defined between the control mechanism (150) and the switch under controlled atmosphere (100) so that the latter is only activated after crossing this game.  18. Device according to one of claims 5 to 17, characterized in that the spring (180) of the control mechanism (150) is electrically isolated.  19. Device according to one of. Claims 5 to 18, characterized in that the controlled atmosphere switch (100) is arranged in parallel with the disconnector (50).  20. Device according to one of claims 5 to 19, characterized in that the switch under controlled atmosphere (100) is arranged in series with the disconnector (50).  21. Device according to claim 13, characterized in that the opening lever (195) and the closing lever (190) are formed of a V-shaped plate (1900) made of electrically conductive material.  22. Device according to claim 21, characterized in that there are provided two plates (1900) connected by an upper element (1902) of electrically insulating material.  23. Device according to one of claims 1 to 22, characterized in that it comprises a frame (10) formed of two adjustable telescopic elements (1000, 1002).  24. Device according to one of claims 1 to 23, characterized in that the electrically conductive bar (75) extends over the entire width separating the two flanges (60, 62).  25. Device according to one of claims 1 to 23, characterized in that the electrically conductive bar (75) extends over only part of the width separating the two flanges (60, 62).  26. Device according to claim 25, characterized in that the electrically conductive bar (75) is fixed on one of the two flanges (60).  27. Device according to one of claims 25 or 26, characterized in that the electrically conductive bar (75) extends substantially over 2/3 of the width separating the two flanges (60, 62).  28. Device according to one of claims 25 to 27, characterized in that it further comprises a whip (200) secured to the movable contact (54) and an associated hook (300) secured to the fixed contact (52).  29. Device according to claim 28, characterized in that the whip (200) comprises a base (210) in spiral spring steel and a rod (220) fixed to the base (210) by a ferrule (230).  30. Device according to one of claims 1 to 29, characterized in that the flanges (60, 62) of the clamp of the movable contact are provided with longitudinal slots (80).  31. Device according to claim 30, characterized in that said longitudinal slots (80) open into a flared cutout (84) and have their edges inclined towards the outside to avoid any interference with the blade (52) during the maneuvers .