FR2868198A1 - Locking system for rod of linear mechanical control of high/medium voltage circuit breaker, has balls through which torque is created on inclined flanks and on keyways between splines to drive casing`s movable part around rod - Google Patents

Abstract

The system has multiple balls (6) distributed on the periphery of a rod to cooperate with two circumferential grooves (2A, 2B) formed on the rod. An axial force exerted on the rod creates a torque on inclined flanks of the grooves and on keyways between splines of an annular casing (7), through the balls to drive a movable part of the casing in rotary movement around the rod for liberating translation movement of the rod. An independent claim is also included for a linear mechanical control for a high or medium voltage circuit breaker comprising a locking system.

Description

Locking system for linear control

  The present invention relates to a locking system for immobilizing or releasing the translation movement of a rod of a linear control, the rod being movable in an axial direction between a first position and a second position spaced a certain distance according to the axial direction of the first position.

  The invention more particularly relates to a locking system for a linear mechanical spring control used to move the moving contact crew of a high or medium voltage circuit breaker.

  In such an arrangement, the two positions of the rod of the linear control correspond to the two positions of the movable contact equipment of the circuit breaker. For example, the first position of the rod corresponds to the position of the moving contact crew when the circuit breaker is open and the second position of the rod corresponds to the position of the moving contact crew when the circuit breaker is closed. Furthermore, the translation movement of the rod in the axial direction is maintained by springs and in particular helical springs which serve to store the kinetic energy to perform successive switching of the circuit breaker.

  Patent document US2003 / 0034331 discloses a linear control of the type indicated above with a locking system for immobilizing or releasing the translation movement of the rod. This locking system is constituted by a pawl controlled by an electric coil. A snap locking system is not suitable for spring loaded controls with springs exerting significant forces on the rod. In addition, this type of locking system is not adapted to lock the position of the rod in both directions of movement of the rod in the axial direction.

  Also known from patent document EP0801406, a linear mechanical control springs for high voltage circuit breaker which comprises a locking system with several pawns controlled by electric coils.

  Patent document EP1123571, a control for a high-voltage circuit breaker in which the locking system is constituted by an electric motor which moves a rod of the control by means of a complicated kinematic chain to transform a movement, is still known. rotary engine in a translational movement of the rod. Such an arrangement also has the disadvantage of being unstable to lock the position of the rod.

  The object of the invention is to provide a locking system for immobilizing or releasing the translational movement of a rod of a linear control for high or medium voltage circuit breaker for example, which is reliable and fast and which supports axial forces the rod during switching operations of the circuit-breaker.

  For this purpose, the subject of the invention is a locking system for immobilizing or releasing the translational movement of a rod of a linear control, the rod being movable in an axial direction between a first position and a second position spaced apart by a certain distance in the axial direction of the first position, characterized in that it comprises two circumferential grooves formed on the rod and spaced from each other in the axial direction of said certain distance and a plurality of balls distributed over the periphery of the rod to cooperate with said circumferential grooves, said balls being mounted in an annular cage surrounding the rod, said annular cage comprising a first annular portion fixed in the axial direction, surrounding the rod and traversed by the balls and a second movable portion relative to the fixed annular portion, surrounding the first annular portion with the balls and ag enco rotational or translationally driven relative to the first annular portion under the effect of an axial force exerted on the rod to release the translational movement of the rod.

  According to a particular embodiment of the locking system according to the invention, the cage is arranged so that a rotational movement of the mobile part around the rod in a first angular direction causes the release of the translation movement of the rod. in one direction and a rotational movement of the movable part around the rod in an opposite direction causes immobilization of the translation movement of the rod.

  According to another particular embodiment of the locking system according to the invention, the cage is arranged so that a translational movement in the axial direction of the movable part in a first direction causes the release of the translation movement of the rod. and that a translational movement of the movable part in a reverse direction causes immobilization of the translation movement of the rod.

  According to another particular embodiment of the locking system according to the invention, the mobile part comprises grooves in which the balls are introduced when the moving part occupies an angular position which causes the release of the translational movement of the rod and wherein the movable portion has between two consecutive grooves an inner surface which forms a ramp on which the balls move.

  According to another particular embodiment of the locking system according to the invention, the mobile part comprises a circumferential groove in which the balls are introduced when the movable part occupies a position in the axial direction A which causes the release of the movement of translation of the rod and wherein a flank of the circumferential groove is interrupted to extend into a frustoconical bore which forms a ramp on which the balls move.

  According to another particular embodiment of the locking system according to the invention, the circumferential grooves have inclined flanks with respect to the axis of the rod.

  According to another particular embodiment of the locking system according to the invention, the mobile part is immobilized and mobilized by means of an electromagnet.

  According to a particular embodiment of the locking system according to the invention, the locking system comprises a return spring which opposes the rotational movement or translation of the movable part.

  With the arrangement of the locking system according to the invention, an axial force exerted on the rod of the linear control creates a torque by the interaction of the balls on the inclined sides of the grooves and on the ramps between the grooves of the cage which tends to drive the mobile part of the cage in a rotary movement around the rod so that it is sufficient to release the rotary movement of the movable part of the cage to release the translational movement of the rod. As a result, the release of the translation movement of the rod can be performed in both directions of the axial direction and this quickly with little energy.

  An example of a first embodiment of the locking system according to the invention is described in more detail below and illustrated by the drawings.

  FIG. 1 very schematically shows a linear mechanical control with springs fitted to a high-voltage circuit breaker and equipped with a locking system according to the invention.

  FIG. 2 shows an enlarged view of the linear spring mechanical control of FIG. 1 with the locking system according to a first embodiment of the invention.

  Figure 3 is a partial schematic sectional view along A-A in Figure 4 of the annular cage of the locking system according to a first embodiment of the invention.

  Figure 4 is a radial sectional view of the annular cage of the locking system according to a first embodiment of the invention.

  Figure 5 is an enlarged view in radial section of a portion of the cage of the locking system according to a first embodiment of the invention.

  Figure 6 schematically illustrates the locking system with an electromagnet for blocking the rotary motion of the annular cage according to a first embodiment of the invention.

  Figure 7 is a partial schematic sectional view along the axial direction A of the locking system according to a second embodiment of the invention.

  FIG. 8 illustrates a schematic partial sectional view along the axial direction A of the locking system according to a third embodiment of the invention.

  FIG. 1 very schematically shows an exemplary application of the locking system according to the invention for a linear mechanical control with springs fitted to a high-voltage circuit breaker 1. The circuit breaker 1 is shown here in the open position. The rod 2 of the linear mechanical control 3 is integral in motion of the movable contact 4 of the circuit breaker 1 which is separated here from the fixed contact of the circuit breaker.

  FIG. 1 shows two springs 3A and 3B of the linear mechanical control 3 which are respectively the trigger spring for opening the circuit breaker and the closing spring for closing the circuit breaker. As shown in Figure 1, the tripping spring 3A is expanded while the closing spring 3B is compressed and ready to drive the rod 2 in the axial direction A for switching the circuit breaker in the closed position. The locking system 5 according to the invention blocks the translation movement of the rod 2 in the axial direction A. FIG. 2 is an enlargement of the linear spring control 3 shown in FIG. 1, according to a first embodiment of FIG. the invention.

  As can be seen in FIG. 2, the rod 2 is provided with two circumferential grooves 2A, 2B spaced apart from one another in the axial direction A by a distance corresponding to the distance traveled by the rod 2 when it is displaced. between a first position corresponding to the closing position of the circuit breaker and a second position corresponding to the open position of the circuit breaker.

  In Figure 2, we see that the locking system 5 is engaged in the groove 2B of the rod 2 and keeps the circuit breaker in the open position.

  The locking system 5 is shown according to the first embodiment. However, it will be seen later that a locking system according to a second and a third embodiment of the invention can be applied to the linear control 3. The locking system 5 comprises a plurality of balls 6 distributed over the circular periphery of the rod 2 to cooperate with one of the grooves 2A or 2B of the rod. The balls 6 are mounted in an annular cage 7 fixed via a disk 8 to the tubular housing 9 of the control 3.

  As shown in Figure 2, two support discs 10 and 11 are fixedly mounted in the axial direction A, being spaced apart from each other in the axial direction A between the two springs 3A and 3B. These two disks 10, 11 are engaged in the tubular housing 9 of the control 3. Furthermore, two other support discs 12, 13 are arranged on either side of the pair of disks 10 and 11 in the direction axial A, these discs 12, 13 being integral and movable in the axial direction A with the rod 2. The two springs 3A, 3B are helical springs which are arranged coaxially with respect to each other around the rod 2 The triggering spring 3A, which is disposed here between the locking system 5 and the engaging spring 3B, is held between the discs 10 and 12 while the engaging spring 3B is held between the discs 11 and 13. Due to the position of the rod 2 in Figure 1 relative to the fixed disks 10 and 11, the interlocking spring 3B maintained compressed between the disks 11 and 13 exerts on the rod 2 an axial force which tends to move the rod 2 in the axial direction upwards in FIG. so that release of the locking system 5 (release of the balls 6 of the groove 2B) will cause the switching of the circuit breaker 1 in the closed position parallel to the compression of the spring 3A between the disks 10 and 12. In the closed position of the circuit breaker 1, the groove 2A is in front of the locking system 5 which can be operated as described below to lock the translational movement of the rod.

  It is therefore understood that the expansion of the trip spring 3A causes the compression of the interlocking spring 3B and vice versa and that kinetic energy is transferred from one spring to the other. The kinetic energy losses during successive switches of the circuit breaker are compensated by an electrical equipment 14 placed between the two fixed springs 3A, 3B to drive and control the translational movement of the rod 2 in the axial direction A. FIG. a partial view in schematic section along AA in Figure 4 of the annular cage 7 of a first embodiment of the locking system 5 according to the invention. As can be seen in FIG. 3, the annular cage 7 comprises a ring-shaped first ring-shaped portion 7A which is rotatable about a second ring-shaped, fixed annular portion 7B, which ring surrounds the rod 2 and is secured to each other. of the housing 9 of the control via the disk 8 (not shown in this figure).

  As can be seen in FIG. 3, the rotatable annular portion 7A is disposed between a circumferential outer rib 7B 'of the fixed annular portion 7B and a set of clamping rings 7B "which press the annular portion 7A against the rib 7B.

  The annular portion 7B comprises a set of radial holes 7C 'in which are housed respectively the balls 6. In Figure 3, we see that the balls 6 are engaged both in the holes 7C' and in the groove 2B to achieve a blocking the movement of the rod 2 in the axial direction A. As seen in FIG. 3, the circumferential groove 2B (like the groove 2A) has flanks 2B 'which are not perpendicular with respect to the axis of the rod 2 but which are inclined at an angle ss (of the order of 60) relative to the axis of the rod 2. More particularly, in section the groove forms a U whose branches are flaring towards the opening of the U so as to form each a sort of ramp for the balls 6.

  The arrow FS shows the force exerted by the engagement spring 3B on the rod 2.

  The arrow FR1 represents a radial reaction force exerted on each ball 6 by the inclined side 2B 'of the groove 2B. It will be understood that the direction of the force FR1 is perpendicular to the axial direction A. In FIG. 4, a schematic radial sectional view of the annular cage 7 of the locking system 5 according to the first embodiment of FIG. invention in which the fixed annular portion 7B and the annular movable ring portion 7A are seen. The movable annular portion 7A comprises splines 30 distributed on the inner periphery whose number is identical to the number of balls 6 and in each of which a ball is retracted to clear the circumferential groove 2B (or the groove 2A). Each groove extends perpendicular to the axis of the rod 2. Each groove 30 extends perpendicularly to the axis of the rod 2. The depth of the grooves 30 is slightly greater than the depth of the groove 2B (or throat 2A).

  As shown in Figure 4, each groove has a cross section in the shape of "U", the branches of the "U" flaring towards the opening of the "U". More particularly, each groove has two flanks 31 which are inclined with respect to a radial direction of an angle of 30, for example.

  Moreover, as it appears even better in FIG. 5, it can be seen that the junction zone between two consecutive splines on the inner surface of the mobile annular part 7A also defines a kind of ramp 32 which rises on the inside of the portion 7A of the cage to join the edge of an inclined flank 31 of a groove 30 (the left flank in Figure 5). The ramp 32 is arranged so that the axial reaction force FR1, transmitted via each of the balls 6 to the corresponding ramp 32, generates a tangential component FR2. The latter tends to impose a rotational movement on the mobile part 7A of the annular cage 7. The direction of the force FR2 is the line perpendicular to the direction of FR1. The force FR2 is applied to the point of contact between the ball 6 and the corresponding ramp 32.

  In our first embodiment, said ramp is an inclined plane of angle a (of a few degrees) with respect to the line perpendicular to the direction of FR1. In the stationary position of the rod 2, the balls 6 are held in the holes of the part 7B on one side by the groove 2B (or 2A) and on the other by the ramp 32. Of course, the ramp 32 could not not have a flat surface.

  The combination of all the FR2 forces produced by the balls 6 on the ramps 32 is a pair MR2 which acts to rotate the movable portion 7A of the annular cage 7 in the direction indicated by the arrow MR2 (trigonometric direction). As can be understood in FIG. 4, the rotation of the mobile part 7A of the annular cage 7 in the direction of MR2 causes the balls 6 to coincide with the grooves 30, which allows the balls 6 to be released from the groove. groove 2B and thus the release of the translational movement of the rod 2. The value of the torque MR2 can be optimized by the choice of the angles a and ss, according to the following simplified relationship: MR2 = r * tg (a) * tg (ss ) * FS where r denotes the radius of the center of the cage 7 at the point of support considered of a ball on a corresponding ramp 32 and tg denotes the tangent trigonometric function.

  This relation does not take into account the coefficients of friction.

  FIG. 6 diagrammatically shows an electromagnet 40 and a return spring 41 which respectively serve to block the rotational movement of the part 7A of the annular cage and to bring this part 7A back to a locking position. of the annular cage. The electromagnet 40 is fixed to a frame 42 disposed inside the casing 9 and comprises for example a "U" shaped magnet 43, a rotating part 44 arranged in the air gap of the magnet, a finger of support and a return spring 46. As visible in Figure 6, the movable portion 7A of the annular cage 7 has a radial handle on its outer periphery whose end is in abutment against the workpiece 44. The MR2 couple exerted on the The annular cage is indicated in FIG. 6 and it can be seen that the return spring 41 exerts a force on the handle of the movable part 7A which opposes the pair MR2. In Figure 6, the piece 44 is locked in position, pressing the support of the electromagnet on one side and pulled by the return spring 46 on the other side.

  In response to an electrical pulse applied to the magnet 43, the part 44 is rotated in the air gap of the magnet 43, which consequently releases the rotary movement of the annular cage 7 in the trigonometrical direction indicated by the arrow MR2. The rotation of the annular cage in the direction of MR2 causes a rise of the balls 6 in the grooves 30 and thus the release of the translational movement of the rod 2. This results in a circuit breaker switching in a closed position. In this position of the circuit breaker, the annular cage 7 surrounds the annular groove 2A. Under the action of the return spring 41 tending to rotate the movable portion 7A of the annular cage 7 in the opposite direction of the trigonometric direction, the balls 6 are engaged in the circumferential groove 2A for a new locking of the movement in translation of the rod 2 while the rotary part 44 is brought into a locking position under the action of the return spring 46 stretched between the piece 44 and the finger 45.

  The locking system 5 operates in the same way for switching the circuit breaker from a closed position to an open position.

  With the arrangement of the locking system according to a second embodiment of the invention, an axial force exerted on the rod of the linear control creates a torque by the interaction of the balls on the inclined sides of the grooves of the rod and on the ramp in the extension of a flank of the groove of the movable part which tends to drive the mobile part of the cage in a translation movement in the axial direction so that it is sufficient to release the translational movement of the moving part of the cage to release the translational movement of the rod. As a result, the release of the translation movement of the rod can be performed in both directions of the axial direction and this quickly with little energy.

  FIG. 7 illustrates a schematic partial sectional view along the axial direction A of the locking system according to a second embodiment of the invention.

  The locking system according to the second embodiment of the invention is applied to a mechanical spring drive for a high and medium voltage circuit breaker as described in the first embodiment and illustrated above by FIGS. 1 and 2. Figure 7 shows the rod 2 of the control with the grooves 2A and 2B. The locking system 5 here comprises an annular cage 77 surrounding the rod 2 and in which the balls 6 are arranged. The annular cage 77 comprises a ring-shaped fixed annular portion 77B having radial holes distributed over its circular periphery in which are The annular portion 77B is fixed to the housing 9 (not shown in FIG. 7) via the disc 78. The annular cage 77 also comprises an annular portion in the form of a cylindrical sleeve 77A fitted on the end. of the rod 2 and which surrounds the ring-shaped annular portion 77B. The sleeve-shaped portion 77A is movable in the axial direction A. The sleeve-shaped movable portion 77A includes an inner circumferential groove 730 which surrounds the fixed ring 77B and wherein the plurality of balls 6 retract when the bushing Mobile 77A occupies a certain position along the axis A corresponding to the release of the translation movement of the rod 2. The depth of the groove 730 is slightly greater than the depth of the groove 2B (or the groove 2A). This groove 730 has flanks 731 inclined at an angle of 30, for example, with respect to a radial direction. One of the flanks 731 is interrupted to extend into a frustoconical bore which tapers towards the axis A towards the bottom of the movable bushing 77A to form an annular ramp 732. In our embodiment, said ramp 732 is a plane inclined by a few degrees with respect to the axial direction A and a function similar to the plane 32 in FIG.

  It can be seen in FIG. 7 that the plurality of balls 6 is engaged on one side in the groove 2B and held on the other by the ramp 732. The rod 2 of the control is thus kept in the stationary position. By the arrow FS is shown the force exerted by the engagement spring 3B on the rod 2. The arrow FR1 represents the reaction force transmitted through the plurality of balls 6 to the movable sleeve 77A. It will be understood that the direction of the force FR1 is the radial direction at the point of contact between the corresponding ball 6 and the ramp 732. This force FR1 is thus applied to the ramp 732 so that it generates an axial force FR2 'acting to drive the translational movement of the movable bushing 77A in the opposite direction of the force FS of the interlocking spring 3B.

  This translational movement of the movable sleeve 77A is blocked by an electromagnet 73, similar to that of the first embodiment and fixed to the housing 9 (not shown in Figure 7).

  The electromagnet 73 controls, by means of a rotating part 74, the rotation of a rod-shaped rod 75 mounted on a pivot and connected by an oblong hole to the movable bushing 77A, so that Rotation of the rotating part 74 causes, via the rod 75, the release of the translational movement of the movable sleeve 77A driven under the effect of the force FR2 '.

  The balls 6 then move in the holes of the fixed ring 77B and retract in the groove 730 of the movable sleeve 77A. The rod 2 is released and undergoes translational movement driven by the force FS. This results in a circuit breaker switching in the closed position. In this position of the circuit breaker, the groove 730 of the movable sleeve 77A faces the circumferential groove 2A.

  A return spring 71, disposed coaxially with the rod 2 between an abutment 76, integral with the housing 9, and the outer bottom of the bushing 77A, acts to return the latter to the position of immobilization of the rod, that is to say in the direction of the FS force. As shown in Figure 7, the bottom of the movable sleeve 77A is enlarged so as to abut on a disk 76 ', integral with the housing 9, thus limiting its stroke in the direction of the force FS. The disc 76 'surrounds and guides the movable sleeve 77A through a spacer 79 with a low coefficient of friction. A second spacer 79 'with a low coefficient of friction secured to the fixed ring 77B guides and facilitates the sliding of the movable sleeve 77A.

  The balls 6 move in the holes of the fixed ring 77B and retract into the groove 2A of the rod 2, pushed by the ramps 731 and 732 of the movable sleeve 77A. The electromagnet acts to hold still the rod 2 of the control in this closed position of the circuit breaker.

  The locking system according to the second embodiment operates in a similar manner for switching the circuit breaker from a closed position to an open position.

  With the arrangement of the locking system according to a third embodiment of the invention, an axial force exerted on the rod of the linear control creates a torque by the interaction of the balls on the inclined flanks of the grooves of the rod and on the ramp in the extension of a flank of the groove of the movable part which tends to drive the mobile part of the cage in a translation movement in the axial direction so that it is sufficient to release the translational movement of the moving part of the cage to release the translational movement of the rod. As a result, the release of the translation movement of the rod can be performed in both directions of the axial direction and this quickly with little energy.

  FIG. 8 illustrates a schematic partial sectional view along the axial direction A of the locking system according to a third embodiment of the invention.

  The locking system according to the third embodiment of the invention is applied to a mechanical spring drive for a high and medium voltage circuit breaker as described in the first embodiment and illustrated above by FIGS. 1 and 2. Figure 8 shows the rod 2 of the control with the grooves 2A and 2B. The locking system 5 here comprises an annular cage 87 surrounding the rod 2 and in which the balls 6 are arranged. The annular cage 87 comprises a ring-shaped first annular portion 87B having radial holes distributed over its circular periphery in which the balls 6 are arranged. The annular portion 87B is fixed to the casing 9 (not shown in FIG. 8) by means not shown in FIG. 8. The annular cage 87 also comprises a second cylindrical movable part 87A in the form of a ring surrounding the fixed annular portion 87B. The cylindrical movable portion 87A is movable in translation in the axial direction A. A third fixed portion 84 in the form of an open bottom sleeve surrounds the movable portion 87A. The sleeve 84 fitted by the end of the rod 2 has its bottom open to let the rod 2 during its translational movement and is integral with the fixed annular portion 87B.

  The movable ring 87A is provided with an inner circumferential groove 830 which surrounds the fixed ring 87B and in which the plurality of balls 6 retract when the movable ring 87A occupies a certain position along the axis A corresponding to the release the translation movement of the rod 2. The depth of the groove 830 is slightly greater than the depth of the groove 2B (or the groove 2A). This groove 830 has flanks 831 inclined at an angle of 30, for example, with respect to a radial direction. One of the flanks 831 is interrupted to extend into a frustoconical bore which tapers towards the axis A going towards the bottom of the bushing 84 to form an annular ramp 832. In our embodiment, said ramp 832 is a inclined plane of a few degrees with respect to the axial direction A. An annular spacer 83 with a low coefficient of friction fixed to the fixed ring 87B promotes the sliding of the movable ring 87A.

  It can be seen in FIG. 8 that the plurality of balls 6 is engaged, on one side, in the groove 2B and held on the other by the ramp 832. The control rod 2 is thus kept in a stationary position. By the arrow FS is shown the force exerted by the engagement spring 3B on the rod 2. The arrow FR1 represents the reaction force transmitted through the plurality of balls 6 to the movable ring 87A. It is understood that the direction of the force FR1 is the radial direction at the point of contact between the corresponding ball 6 and the ramp 832. This force FR1 is therefore applied to the ramp 832 so that it generates an axial force FR2 'acting to cause the translational movement of the movable bushing 87A in the opposite direction of the force FS of the engagement spring 3B. This translational movement of the movable bushing 87A is blocked by an electromagnet (not shown in FIG. 8) fixed to the housing 9.

  In this third embodiment, the open-bottomed bushing 84 comprises an opening arranged to allow an "L" -shaped rod 85 connected to the movable ring 87A to move. The connecting rod 85 is connected outside the cage 87A to the electromagnet (not shown in FIG. 8) via a rotating part (not shown in FIG. 8), so that a rotation of the latter causes, via the connecting rod 85, the release of the translational movement of the movable ring 87A driven under the effect of the force FR2 '.

  The balls 6 then move in the holes of the fixed ring 87B and retract in the groove 830 of the movable ring 87A. The rod 2 is released and undergoes a translational movement driven by the force FS. This results in a circuit breaker switching in the closed position. In this position of the circuit breaker, the groove 830 of the movable ring 87A faces the circumferential groove 2A.

  A return spring 81, coaxially disposed to the rod 82 between the bottom of the bushing 84 and the movable ring 87A, acts to bring the movable ring 87A back in the direction of the force FS.

  The balls 6 move in the holes of the fixed ring 87B and retract into the groove 2A of the rod 2, pushed by the ramps 831 and 832 of the movable ring 87A. The electromagnet acts to hold still the rod 2 of the control in this closed position of the circuit breaker.

  The locking system according to the third embodiment operates in a similar manner for switching the circuit breaker from a closed position to an open position.

  The locking system according to the invention can be applied to a linear mechanical spring control for high or medium voltage disconnector or to a linear mechanical control with springs for high or medium voltage earthing switches.

  The linear electrical equipment 14 for driving and controlling the movement of the control rod 2 may be, for example, a servomotor connected to a rack. It is possible to replace the springs of the control completely and to control and control the movement of the rod by this servomotor only.

  The angle of inclination of the flanks of the grooves 2A, 2B and 32, 732, 832 planes may be chosen so as to obtain a rolling of the balls in the annular cage rather than sliding.

Claims (11)

  1 / locking system for immobilizing or releasing the translational movement of a rod (2) of a linear control, the rod being movable in an axial direction (A) between a first position and a second position spaced from a certain distance in the axial direction of the first position, characterized in that it comprises two circumferential grooves (2A, 2B) formed on the rod and spaced from each other in the axial direction of said certain distance and a plurality balls (6) distributed over the periphery of the rod to cooperate with said circumferential grooves, said balls being mounted in an annular cage (7, 77, 87) surrounding the rod, said annular cage comprising a first annular portion (7B, 77B , 87B) fixed in the axial direction, surrounding the rod and traversed by the balls and a second portion (7A, 77A, 87A) movable relative to the fixed annular portion (7B, 77B, 87B), surrounding the first annular portion with the balls and arranged to be driven in rotation or translation relative to the first annular portion under the effect of an axial force exerted on the rod to release the translational movement of the rod.   2 / locking system according to claim 1, wherein the cage (7) is arranged so that a rotational movement of the movable portion (7A) around the rod in a first angular direction causes the release of the translational movement of the rod in one direction and a rotational movement of the movable part (7A) around the rod in an opposite direction causes immobilization of the translation movement of the rod.   3 / A locking system according to claim 1, wherein the cage (77, 87) is arranged so that a translation movement in the axial direction (A) of the movable part (77A, 87A) in a first direction causes releasing the translation movement of the rod and translational movement of the movable portion (77A, 87A) in an opposite direction causes immobilization of the translation movement of the rod.   4 / A locking system according to claim 2, wherein the movable portion (7B) comprises grooves (30) in which are introduced the balls (6) when the movable portion occupies an angular position which causes the release of the movement of translation of the rod and wherein the movable portion has between two consecutive grooves an inner surface which forms a ramp (32) on which the balls move.   5 / A locking system according to claim 2, wherein the movable portion (77A, 87A) comprises a circumferential groove (730, 830) into which is introduced the balls (6) when the movable portion occupies a position in the direction axial A which causes the release of the translation movement of the rod and wherein a flank of the circumferential groove (730, 830) is interrupted to extend into a frustoconical bore which forms a ramp (732, 832) on which move the marbles.   6 / A locking system according to one of claims 1 to 5, wherein the circumferential grooves (2A, 2B) of the rod have flanks inclined relative to the axis of the rod.   7 / A locking system according to claims 1 to 6, wherein the movable portion (7A, 77A, 87A) is immobilized via an electromagnet (40, 70).   8 / locking system according to claims 1 to 7, comprising a return spring (41, 71, 81) which exerts a force in a direction opposite to the rotational movement or translation of the movable part (7A, 77A, 87A) .   9 / linear mechanical control for high or medium voltage circuit breaker comprising a locking system according to one of claims 1 to 8.   10 / linear mechanical control for high or medium voltage disconnector comprising a locking system according to one of claims 1 to 8.   11 / Linear mechanical control for high or medium voltage earthing switches including a   interlock according to one of claims 1 to 8.