FR2713821A1 - Switch-disconnector for breaking under load. - Google Patents

Abstract

A switch-disconnector has a fixed contact (13) which is mounted on a base (10) and is insulated from it as well as a contact (15) which is fixed, at the free end of a lever pivoting (18) articulated on the base (10) and is movable relative to the fixed contact (13). An additional fixed contact (14) is also fixed on the base and is insulated from it. The movable contact (15) is freely linked in rotation to the pivoting lever so that in the closed, open position, it provides an electrically conductive connection between the two fixed contacts (13, 14).

Description

Switch-disconnector for breaking under load The present invention

  concerns a load-break switch-disconnector comprising a fixed contact which is fixed to

  a base being isolated from the latter, an additional fixed contact

  which is fixed on the base and is also insulated from it and a pivoting lever of insulating material which is articulated on the base and whose free end carries a movable contact which, relative

  in fixed contact, is in the form of an elongated element of long

  such that in the closed, on position, the movable contact bridges the distance between the two fixed contacts, the movable contact being guided with the possibility of sliding in the additional fixed contact and

  being linked with possibility of rotation to the free end of the pivot lever

  both in such a way that in the closed, on position, the movable contact connects together, in an electrically conductive manner, the two fixed contacts

  and the additional fixed contact being disposed in a tubular housing

  re which is closed at its end remote from the contacts and in which the

moving contact penetrates.

  A switch-disconnector is an electrical switching device which can authorize and interrupt the passage of a nominal current in an electrical network and in which a distance between contacts defined by specifications must be maintained in position

  of interruption. Unlike separators in which the community

  tation must not take place under load, a switch-disconnector must be able to withstand an electric arc whose power is dependent

  nominal voltage or nominal current to be switched.

  A switch-disconnector for medium voltage can consist for example of a vacuum switch; switch disconnectors are also known in which the arc which forms during switching is blown by means of an electrically negative gas,

  preferably using SF6 gas.

  Switch-disconnectors of this type are relatively expensive, in particular because they have to operate under a

SF6 gas atmosphere.

  The objective of the present invention is to provide an inter-

  switch-disconnector whose layout in terms of construction is simplified but whose ability to switch at nominal power

is kept.

  This objective is achieved in accordance with the invention by the fact that each fixed contact has a contact box with inside of it contact fingers between which the movable contact can

  slide, by the fact that the fixed contact and the fixed contact supplement

  each are arranged in a contact box, preferably square, boxes which, at least in the closed, passing position, surround the movable contact and in the facing walls of which the contact fingers are mounted elastically with the possibility of rotation and displacement in direction of each other, by the fact that a contact rod is associated with the additional fixed contact and that a contact tube is associated with the movable contact, the contact tube freely surrounding the contact rod in the closed, on position, and by the fact that a gas flow is generated through the contact tube during the

  disconnection, when the movable contact is far from the fixed contact.

  In accordance with the invention, the movable contact has a contact carrier with a cross section in the form of a flattened rectangle, of which

  the plane defined by the longest axis extends in the pivot plane.

  The contact carrier is covered with a U-shaped cap which constitutes the movable contact, the core of which extends in the direction of movement of the movable contact and the branches of which are oriented in

  direction of the pivot axis of the pivot lever. The hat in form

  me de U is made of a material resistant to electric arcs and is simultaneously in sliding connection ensuring the passage of current

  electric with the contact fingers of the additional fixed contact.

  According to one embodiment of the invention, the contact fingers in each fixed contact are arranged opposite

  in pairs and are elastically prestressed towards one of the other

  tre and the movable contact slides between said contact fingers during switching. According to one embodiment of the invention, the contact fingers of each fixed contact and their contact surface are arranged in a contact box, preferably square, and protrude

  of the latter in the direction of the fixed contact located opposite.

  In accordance with one embodiment of the invention, the tu-

  be contact has a reduced section which surrounds the contact rod without play and is flared towards the outside. The contact tube has an extension which extends in the direction of the fixed contact. In accordance with one embodiment of the invention, the movable contact is housed in an envelope and a piston assembly which

  is mounted on the movable contact is guided with the possibility of sliding

  inside the said envelope. The cylinder of said assembly

  is formed by the envelope, so that during cutting, a vo-

  the light between the piston and the bottom of the envelope is compressed and the gas contained in this volume is brought through the tube

contact to the point of contact.

  According to one embodiment of the invention, the rod

  contact is guided with the possibility of sliding along a path

  jectory determined inside an envelope which is fixed on the

  base via an isolator-support. In an iron position

  mée, passer-by, the contact rod is pushed back by the movable contact tube against the pressure of a spring so that the contact rod, during the cut follows the movable contact tube for a certain distance . There may be provided, inside the envelope of the fixed contact, a square box which is crossed by the contact rod and in which is disposed the spring which on one side bears on a wall of the box through which the rod and the other on a shoulder

of the contact rod.

  In accordance with one embodiment of the invention, the

  fixed contact housing has a pivoting latching lever

  which hooks a chin provided on the mobile contact

the.

  During cutting, the chin on the movable contact

  do the snap lever and with it the contact rod. It can unhook after having traveled a certain stroke, so that the contact rod does not move away from the contact tube until after having traversed said stroke. After stalling, the contact rod is returned to its

starting position by the spring.

  The free end of the fixed rod-shaped contact and the ex-

  free end of the moving contact facing the other contact can

  have an area made of material resistant to electric arcs.

  In accordance with an embodiment of the invention, a fixed earthing contact, in which the pivoting lever engages

  of a grounding contactor, is connected to the fixed contact.

  In accordance with an improvement of the invention, the iso-

  reader-holders for supporting fixed contacts have at least one protruding circular edge which increases the line length

leak.

  In accordance with one embodiment of the invention, it is provided above the movable contact, seen from the fixing plane of

  the switch-disconnector, a guide roller which prevents displacement

  cement up the movable contact.

  In accordance with an improvement of the invention, the

  contact fingers are retained laterally each by a yoke.

  In accordance with an improvement of the invention, the re-

  Section of nozzle-shaped section is surrounded by a control electrode. The branches of the mobile contact are fixed on a support, preferably are riveted thereon, and the distance between the branches

  decreases in the fixation region.

  According to the invention, the switch-disconnector comprises

  carries two fixed contacts, a movable contact which is driven by a

  to pivot and an auxiliary contact which during an interruption operation captures the electric arc and the blast so that the two fixed contacts and the movable contact do not have to route said arc,

  said contacts not being designed for this.

  In order to form the auxiliary contact or the commu-

  tation, a contact tube is associated with the additional fixed contact and a contact rod or bar is associated with the fixed contact, which contact rod or bar follows the movement of the contact tube during

  the cutoff and deviates from it after traveling a certain distance

  tance. The movable contact comprises a piston system which during

  the shutdown operation compresses the air or gas inside

  the housing and pushes it through the contact tube or the element

  tubular. Thus the arc which forms at the time of the cut is blown out. The tubular element comprises a tight part in the form of a nozzle which surrounds without play the fixed contact or the contact rod; during cutting, the rod slides in this constricted part thus creating a stroke part during which the contacts remain closed and the gas is compressed. As soon as the contact rod has passed the tightened part, the

  pressurized gas is released and the arc formed is blown out.

  The invention as well as advantageous arrangements thereof and various other advantages are described in the following with the aid of two embodiments shown in the drawings. These show: FIG. 1, a side view of a switch-disconnector according to the invention in the open, non-passing position, FIG. 2, a side view in perspective of the fixed contact with the contact fingers, FIG. 3 , a sectional view along line III of Figure 1, Figure 4, a fixed contact according to another embodiment, Figure 5, the movable contact which corresponds to the contact according to Figure 4, the two figures showing a view in perspective in partial section, Figure 6, a view of the interior of the housing according to Figure 5 and

  Figure 7, a perspective view of a detail of the bu-

and the control electrode.

  We will first refer to Figure 1.

  On a base 10, two insulator-supports 11 and 12 are fixed

  at a distance from each other and carry at their respective free ends-

  a first fixed contact 13 and a second fixed contact 14 or

  additional fixed contact. The two fixed contacts 13 and 14 are dis-

  placed opposite each other at the same height, their median axes being mutual-

  closely aligned. A movable contact 15 is guided with the possibility of sliding in the longitudinal direction inside the additional fixed contact 14, the movable contact 15 being held by axis 16

  in the oblong hole 17 of a pivoting lever 18 made of insulating material, the-

  which pivoting lever 18 is rotatably mounted on an operating shaft 19 disposed on the base 10 between the two insulator-supports 11 and 12 and is connected by obstacle to said operating shaft 19 so that

  the pivoting lever 18 pivots when the operating shaft 19 rotates.

  The axis 16 moving along a horizontal trajectory parallel to the base 10 and the lever 18 being pivotally mounted, the oblong hole 17 makes it possible to absorb the pivoting movement of said lever 18 relative to

  axis 16, during movement of the movable contact 15.

  The fixed contact 13 comprises an envelope 20 which forms a one-piece assembly with the insulator-support and in which is housed

a contact finger box 21.

  In the contact region 23a between the movable contact 15 and

  the contact fingers 23 of the fixed contact 13, a stirrup 26 limits the

  lateral flapping of the contact fingers 23, in particular when they

  are thermally and dynamically stressed by the electric current

  than. In the same way, the additional fixed contact 14 whose construction is identical is housed in a contact envelope

  22, a box 21 with contact fingers with contact fingers 23 elas-

  ticks being provided (see also Figure 2).

  There is provision in the region 23a for contact between the mo-

  bile 15 and the fingers 23 of the additional fixed contact 14, a stirrup 31 which limits the lateral movement of the contact fingers. The bracket 31 serves as a cage for a roller 31a for guiding the movable contact 15 (shown in dotted lines in FIG. 1). This avoids an upward movement of the movable contact. The contact fingers 23 come out from the top of the contact finger box 21, each time in the direction of the other

fixed contact.

  Figure 3 shows a sectional view along line III.

  The envelope 22 is placed on the insulator-support 12, or even forms a one-piece assembly with the latter; the contact finger box 21 is mounted and fixed in the envelope and has a plurality of pairs of opposite contact fingers 23 which are elastically prestressed

towards each other.

  The U-shaped movable contact 15 is mounted on a holder

  contact 24 to which are connected two arms 25 and 27 of a fork-shaped support; the branch 28 which is formed in one piece with the

  pivoting lever 18 and in which the oblong hole 17 is fitted

  be between the two branches 25 and 27. The branches 25 and 27 are for

  views each of a bore 30, 32 in which is mounted the axis 16 which passes through the oblong hole 17; the pin 16 is held in place by means of enlarged parts 33 and 34 in the form of a mushroom, which can by

  example in the form of snap-on elements made of ma-

  plastic and are placed outside the branches 25 and 27. The contact carrier 24 and the branches 25 and 27 are surrounded by the movable contact 15 in the shape of a U, the base 36 of which extends in the direction of movement of the movable contact 15 and whose branches 37 and 38 are

  oriented perpendicular to the base, in the direction of the latter.

  The pairs of contact fingers 23 slide with their surfaces

  these contact 23a on the outer face of the movable contact 15 and assu-

thus make contact.

  The length of the movable contact 15 is such that it is in contact ensuring the passage of the electric current with the contact fingers 23 in the closed position, passing and in the open position, not passing. FIG. 2 shows a perspective side view of a box 21 with contact fingers for the contacts 13 and 14. The box 21 with contact fingers has the shape of a square tube with, on its side walls which extend, parallel to the pivot plane of the pivoting lever 18, recesses 39 and 40 in which the different contact fingers 23 are housed and pushed back towards one another by the pressure of springs 41. To cover the parts in which the springs 41 are located, a plate 42 is provided each time which is fixed by means of screws 43 in a housing 44 on the external face of the wall

  comprising the recesses 39 and 40.

  The fixed contacts 13 and 14 are identical in construction. A fixed contact 45, against which the mobile contact of an inter-

  earthing switch 37 can be swiveled, is re-

  linked to the contact finger box 23 and to the contact fingers 23a which are inside of it. The contact parts of the contact fingers pass through a plate 48 or 49 which extends perpendicularly to the contact finger box 20 or 22 and are each surrounded by a flange 50, 51, said flanges being turned one towards

  the other. The guide in the passage of the contact box, with displacement

  easy cementing of the contact fingers 23, is ensured by a contact cage 35 which is preferably in the form of a plastic injection molded part. Simultaneously, this contact cage 35 prevents untimely multiple contacts between the

  contact fingers 23 and the contact box.

  To close the circuit, rotate the pivoting lever 18

  counter clockwise so as to bring it to the re-

  presented in dotted lines, in which the mobile contact can come in

  connection or in contact with the contact fingers of the fixed contact 13.

  The control shaft is provided with a profiled part in order to ensure an obstacle connection between the control shaft 19 and the

swivel lever 18.

  According to the invention, an auxiliary contact is associated with the fixed contacts and with the movable contact, which auxiliary contact is

  visible in Figures 4 and 5, Figure 4 showing a cross-section

  spective in the region of contact 13 and FIG. 5 representing a section in perspective in the region of additional contact with a movable contact; the two contacts, in the position shown on the

  Figures 4 and 5 can be brought into contact with each other.

  Certain elements described above in relation to

  Figures 1 to 3 are not shown again.

  We will now refer to Figures 4 and 5.

  FIG. 4 shows a different arrangement of a switching device 60 associated with a fixed contact 13. A casing 62 is fixed at the same time as the contact box 21 by means of a flange 61 inside the 'envelope 20, envelope inside which is housed a contact holder 63 with a rectangular frame 64 whose narrow side walls 65 and 66 are crossed by a contact rod 67. Inside, that is to say -to say between the two side walls and 66, the contact rod 67 carries a spring stop 67a held by an elastic ring and, between the spring stop 67a and the side wall 66 opposite the contact end 68, a spring compression 69 so that the contact rod 67 which is guided with possibility

  in displacement in translation in the side walls 65 and 66 is re-

  pushed to the left (in the drawing) when closing, the spring

69 being compressed.

  The contact rod 67 passes through an opening 70 of the flange 61 whose dimensions are such that the movable contact 15 according to the figure can pass through the opening 70. Below the contact end 68 is a hook 71 elastic which pivots around an axis

  71a and which for hooking purposes, can engage behind a chin-

  net 89 (see Figure 5) on the contact combined with the contact rod 68 (see below). The movable contact 15, which is shown in the figure, is housed in an elongated casing 80 of cylindrical shape forming a housing. The end of the envelope 80 adjacent to the

  switching according to FIG. 4 is provided with a flange 61 which corresponds to

  lays on flange 81 by means of which the enclosure can be fixed on

  a mounting surface, for example the mounting surface 49 of the

veloppe 22 of figure 1.

  The opposite end of the casing 80 is closed by a bottom 82. The movable contact 15 guided inside the casing 80 comprises a contact tube 83 with an internal bore 84 which, in the neighboring section of the rod contact 67 - away from the end

  free of contact tube 83 - has a reduction in cross section 85

  The inner diameter of which is such that in the closed, on position and during the switching stroke, it surrounds the contact rod without play. Behind the reduction of section 85, that is to say on the side thereof opposite the free end, is a contact cage 86 by means of which an electrically conductive connection can be obtained between the tube contact 83 and the contact rod 67 in the closed position or during the switching stroke, the contact rod or bar 67/68 being pushed against the contact cage 86 by the spring of 69 when the switch-disconnector is in the position closed, busy. The

  inner section of contact tube 83 widens in the form of a nozzle

  then the reduction of section 85 towards the free end.

  The contact tube 83 is disposed in the contact carrier 24 in

  shape of an elongated parallelepiped, the end close to the end

  free mity of the contact tube 37 carries a chin 89 behind which the elastic hook 71 engages in the closed position. The support 24 is connected to the core 91 of the U-shaped contact 15 by means of hollow rivets 90. The two branches 37 and 38 and the core of the U are only partially visible in the figure (see also the figure 6). It can be seen in FIG. 5 that the distance between the arms 37, 38 is shorter in the region of the rivets 90, which, during the switching stroke, makes it possible to temporarily obtain lower friction between the contact fingers 23 the additional fixed contact 14 and the movable contact 15 at the outer faces of the branches thereof, since the contact fingers do not bear on the movable contact 15 in the narrower region. In addition, the contact fingers 23 of the additional fixed contact 14 are cleaned each time the contact fingers 23 pass from the narrowed area to the area

  of normal thickness of the movable contact 15.

  A piston assembly 94 which is rigidly connected to the movable contact 15 via a screw connection 95 is arranged in the region of the bottom 82, the piston assembly 94 comprising three beads 96a to 98 which project radially and two piston rings 88

  elastics which slide on the inner surface of the envelope 80 cy-

  lindrique. To facilitate understanding we will now refer to

Figure 6.

  The casing 80 contains the piston assembly 94 which is connected to the movable contact 15 via the screw connection 95 and a fixing plate 99 visible in FIG. 6. The figures also show in FIG. branches 37 and 38 as well as the core 36. The movable contact 15 contains contact elements 100 and 101 which form an electrically conductive connection between the contact tube 83 and said contact 15. It is provided on the support 24, in the region of the flange 81 but outside of it, the opening 30, 32 in which for example the axis 16 of the pivoting lever 18 can penetrate or which can be crossed by said

  axis 16. In addition, a lug of the support 24 has an enclosure opening.

  query for synchronous drive of a

speed.

  The end 68 of the contact rod 67 and the contact cage

  86 are made of an electrically good conductive material and

resistant to electric arcs.

  When you have to open the switch, i.e. when

  must bring the switch to a position in which the moving contact

  15 establishes between the additional fixed contact 14 and the fixed contact 13 a connection admitting the required thermal-dynamic current (see FIG. 1) and in which the contact rod 67 is linked to the contact cage 86, in the position shown at Figure 5, we rotate

  or the support 24 is moved to the right and with it the mo-

  bile 15 with the contact tube 83 by means of the pivoting lever 18; the piston 94 meanwhile is moved to the right towards the bottom 82 which results in a reduction of the chamber formed between the piston 102 and the bottom 82. The hook 71 being engaged with the spigot 89 of the support 24 in the closed position , it is first necessary to release this connection by forcing the inclined surface 72 and 73 (of the ribs) onto the

  rollers 74 and 75, that is to say by moving laterally, following

  before a specific stroke during construction, the movable contact 15; during this limited movement, before unlocking, the contact rod 67 is pulled out of the housing 60 by the hook 78 against the force of the spring 79 until the inclined surface 72, 73 arrives on the rollers 74, 75 and the hook pivots downwards. During this movement, switching of the breaking current is ensured by means of the contact cage 86, the contact end 68, the contact rod 67, the contact spring 76, the contact track 77 and the surface of the contact flange 78 applied to the inner face of the contact finger box 21 of the fixed contact 13, the contact

  mobile 15 being moved away from the fixed contact 13. The contact pressure required

  between the contact end 68 and the contact cage 86 is provided by the spring 69. The end of the contact rod 67 being in contact at its end with the contact cage 86 during this partial displacement

  and plugging the orifice 85 of the nozzle, the gas trapped between the piston system

  tone 94 and the bottom, in this case air, is compressed and flows through the internal bore 84 of the contact tube 83 to the orifice 85

  nozzle. After release of the hook 71 by the rollers 74, 75, in the or-

  dre described above and by means of a corresponding displacement, an arc is formed between the contact cage 86 and the end 68 of the contact rod 67 which moves back under the action of the spring 79 which relaxes. It's not

  that from this moment when the electric arc is formed, when the nozzle is

  guaranteed, that compressed gas, air here, passing around the contact cage 86 can blow the electric arc and extinguish it at the next

zero crossing.

  Figure 7 shows in perspective view the details of the bu-

  and an additional control electrode. The contact at the level of the cage 86 is ensured by fitting in the contact tube 83 of three radial wings 86a which have an oversize. The body 97 of the

  nozzle with its port 85 is mounted with obstacle connection as a

  is used in the support 87, with the contact cage 86 and the contact tube 83. There is provided a control electrode 96 which projects into the nozzle body, is partially surrounded by it, can be arranged for example under tube shape and suppresses the electric field of the bridge

  91 in the region of the nozzle and thus optimizes certain phases of commu-

  tation described above for a switch-disconnector.

  The nozzle body which is arranged in the form of an insert can

  be made for example of a special material consisting of a dielectric

  that whose volume which burns under the action of an arc is very small, but has a high surface resistance. For example, it may consist of a molded part made of thermosetting material known under the name PA66, of a special mixture, of a molded mass PUR (polyurethane)

or ceramic.

Claims (22)

  1. Switch-disconnector for breaking under load   both a fixed contact (13) which is fixed on a base (10) being isolated from the latter, an additional fixed contact (14) which is fixed on the base (10) and is also isolated from it ci and a pivoting lever (18) of insulating material which is articulated on the base   (10) and the free end of which carries a movable contact (15) which, by comparison   fixed contact port (13), is in the form of an elongated element   ge, the length of which is such that in the closed, on position, the movable contact (15) bridges the distance between the two fixed contacts (13,   14), the movable contact (15) being guided with the possibility of sliding-   ment in the additional fixed contact (14) and being linked with possibi-   rotation unit at the free end of the pivoting lever (18) so that in the closed, on position, the movable contact (15) connects the two fixed contacts (13, 14) electrically and   the additional fixed contact (14) being arranged in a tubular housing   area which is closed at its end remote from the contacts and into which the movable contact (15) penetrates, characterized in that each   fixed contact (13, 14) has a contact box (21) with inside   of the contact fingers (23) between which the movable contact (15) can slide, by the fact that the fixed contact (13) and the additional fixed contact (14) are each arranged in a contact box ( 21), preferably square, boxes which, at least in position   closed, passing, surround the movable contact and in the facing walls   against which the contact fingers are resiliently mounted with   possibility of rotation and movement towards each other   very, by the fact that a contact rod (67) is associated with the additional fixed contact (14) and that a contact tube is associated with the movable contact (15), the contact tube (83, 84) surrounding without play the contact rod (60; 67, 68) in the closed, on position, and by the fact that a gas flow is generated through the contact tube during cutting, when the movable contact (83, 84) is far from the fixed contact (60, 67, 68).   2. Switch-disconnector for breaking under load according to   claim 1, characterized in that the movable contact (15) pre-   has a contact carrier (24) with a cross section in the form of a rectan   gle flattened, whose plane defined by the longest axis extends in the plane pivot.   3. Switch-disconnector for breaking under load according to   claim 2, characterized in that the contact carrier (24) is   covered by a U-shaped cap which constitutes the movable contact (15), the core of which extends in the direction of movement of the movable contact (15) and the branches of which are oriented in the direction of the axis of   pivoting (19) of the pivoting lever (18).   4. Switch-disconnector for breaking under load according to claim 3, characterized in that the cap (15) in the form of   U is made of a material resistant to electric arcs.   5. Switch-disconnector for breaking under load according to   claim 4, characterized in that the cap (15) is simultaneous   in sliding connection ensuring the passage of electric current   with the contact fingers (23) of the additional fixed contact (14).   6. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that, in each fixed contact (13, 14), the contact fingers (23) are arranged in pairs opposite and are elastically prestressed in   direction of each other and that the movable contact (15) slides between the   so-called contact fingers when switching.   7. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the contact fingers (23) of each fixed contact (13, 14) and their contact surface (23a) are arranged in a contact box (21), preferably square, and protrude therefrom in the direction of contact fixed (13, 14) located opposite.   8. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the contact tube has a reduction in section (85) which   surrounds the contact rod without play and is flared towards the outside   laughing. 9. Switch-disconnector for cut-off under load according to claim 8, characterized in that an extension which extends   in the direction of the fixed contact (13) is arranged on the contact tube.   10. Switch-disconnector for load cut-off according to claim 8 or claim 9, characterized in that the movable contact (83, 84) is housed in an envelope (80), in that a piston assembly (102 ) is mounted on the movable contact (83, 84) guided with the possibility of sliding inside said envelope (80), the cylinder of said assembly being formed by the envelope (80), so that during cutting , a volume between the piston   (102) and the bottom (82) of the envelope is compressed and the gas contains   naked in this volume is brought through the contact tube to point-of-contact.   11. Switch-disconnector for breaking under load according to   any one of claims 7 to 9, characterized in that the   contact rod (60; 67, 68) is guided with the possibility of sliding along a determined trajectory inside an envelope which is fixed to the base (10) by means of a support insulator and   that, in a closed, open position, the contact rod is pushed back   sée by the movable contact tube (83, 84) against the pressure of a spring (69) so that the contact rod (67, 68), during cutting follows a certain stroke the movable contact tube (83, 84). 12. Switch-disconnector for breaking under load according to claim 11, characterized in that there is provided, inside the envelope of the fixed contact (67, 68), a box (64, 65, 66) square which is crossed by the contact rod (67, 68) and in which is disposed the spring (69) which on one side is supported on a wall of the box crossed by the rod and on the other on a shoulder of the contact rod. 13. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that there is provided in the fixed contact housing (67, 68) a lever (71) pivoting snap behind which hangs a chin (89)   provided on the movable contact (83, 84).   14. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that, during cutting, the chin on the movable contact (83, 84) drives the latching lever (71) and with it the contact rod and can come off after having traveled a certain distance, so that the contact rod does not move away from the contact tube until after to have traveled the said race.   15. Switch-disconnector for breaking under load according to claim 14, characterized in that after stalling, the rod   contact is returned to its starting position by the spring (69).   16. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   the free end of the fixed contact (67, 68) in the form of a bar and the free end of the movable contact (83, 84) facing the other contact   have an area made of material resistant to electric arcs.   17. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that a fixed earthing contact (45) into which the pivoting lever (46) of an earthing switch (47) engages is connected to the fixed contact.   18. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the insulator-supports (11, 12) intended to support the fixed contacts (13, 14) comprise at least one projecting circular rim which   increases the line of flight.   19. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that there is provided above the movable contact (15), seen from the fixing plane of the switch-disconnector, a guide roller (3 la) which   prevents upward movement.   20. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the contact fingers (23) are retained laterally each by a stirrup. 21.Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the reduction in section (85) in the form of a nozzle is surrounded by a control electrode (96).   22. Switch-disconnector for breaking under load according to   any one of the preceding claims, characterized in that   that the branches of the movable contact (15) are fixed on a support   (24), preferably are riveted thereto, and by the fact that the distan-   this between the branches decreases in the attachment region.