Control device for actuating at least two items of switchgear in co-ordinated manner, one of which items performs interruption in a vacuum

1. A control device for actuating at least two items of switchgear in co-ordinated manner, which items are electrically connected together in series to constitute a switchgear assembly in which a vacuum first item of switchgear ( 1 ) that performs interruption in a vacuum includes a pair of contacts ( 5 , 6 ) that can be separated to switch from a closed position to an open position, the control device including a main drive shaft ( 2 ) for actuating a second item of switchgear ( 10 ) immersed in a gaseous insulating fluid (G 2 ) contained in a certain volume (V 2 ) at a determined pressure (P 2 ), the control device further including an auxiliary shaft ( 4 ) suitable for being moved by coupling means ( 3 ) to enable a moving contact ( 5 ) of the first item of switchgear ( 1 ) to be driven when said main shaft ( 2 ) is moved, said moving contact ( 5 ) being held pressed against the other contact ( 6 ) of said first item of switchgear ( 1 ), when said first item of switchgear is in the closed position, by a force (F c ) chosen to generate a contact pressure higher than a determined value, said control device being characterized in that said auxiliary shaft ( 4 ) passes in leaktight manner through a wall ( 7 A, 7 ′) which separates said volume (V 2 ) of gaseous insulating fluid (G 2 ) from another volume (V 1 ) of fluid (G 1 ) at a lower pressure (P 1 ), the difference between the respective pressures (P 2 , P 1 ) of the two fluids (G 1 , G 1 ) procuring a certain force (F p ) which is applied to said auxiliary shaft ( 4 ) and which participates in said contact pressure force (F c ).

2. A control device according to claim 1 , in which a portion of said auxiliary shaft ( 4 ) is constituted by a piston ( 4 A) suitable for being moved inside a bore ( 8 ) formed by a part which is mounted in leaktight manner in an opening in said wall ( 7 A), sealing means ( 17 ) for sealing relative to said gaseous insulating fluid (G 2 ) being arranged between said piston ( 4 A) and said bore ( 8 ).

3. A control device according to claim 2 , in which said wall ( 7 A) and said bore ( 8 ) constitute an electrically conductive assembly connected to a pole of the second item of switchgear ( 10 ), said piston ( 4 A) includes at least one electrically conductive portion ( 4 A 2 ) connected to the moving contact ( 5 ) of the first item of switchgear ( 1 ), and sliding contacts ( 9 ) are disposed between said bore ( 8 ) and said conductive portion ( 4 A 2 ) of the piston.

4. A control device according to claim 1 , in which said wall ( 7 A) is constituted by one face of a casing ( 7 ) which encloses at least a portion of said volume (V 2 ) of gaseous insulating fluid (G 2 ) and in which said coupling means ( 3 ) are disposed.

5. A control device according to claim 4 , in which the auxiliary shaft ( 4 ) has an end portion ( 4 B) suitable for sliding in translation in a guide element ( 13 , 13 ′) that is fixed to a face ( 7 B) of the casing ( 7 ) that is opposite the face constituting said wall ( 7 A).

6. A control device according to claim 1 , in which the main shaft ( 2 ) has a segment ( 2 A) that has one side provided with a surface arranged to form a cam ( 30 ) for guiding a rolling element ( 31 ) which is constrained to move with the auxiliary shaft ( 4 ).

7. A control device according to claim 1 , in which said coupling means ( 3 ) comprise resilient compression mechanical means suitable for exerting a force on said auxiliary shaft ( 4 ) for participating in said contact pressure force (F c ) in addition to the force (F p ) procured by the difference in the respective pressures (P 2 , P 1 ) of the two fluids (G 2 , G 1 ).

8. A control device according to claim 7 , in which said resilient compression means comprise a spring ( 35 ) which is mounted on the auxiliary shaft ( 4 ) and which has one end pressing against a pusher element ( 34 ) suitable for being compressed under the action of a finger ( 33 ), said finger being fixed to said main shaft ( 2 ) and arranged to press against said pusher element ( 34 ) when the second item of switchgear ( 10 ) is in the closed position.

9. A control device according to claim 7 , in which said resilient compression means comprise at least one spring ( 36 , 37 ), the resultant force (F r ) exerted by said compression means on said auxiliary shaft ( 4 ) being organized to change direction along the axis (Y) along which said shaft moves in translation while said shaft is moving to open the first item of switchgear ( 1 ), while remaining lower than the force (F p ) procured by the difference in the respective pressures (P 2 , P 1 ) of the two fluids (G 2 , G 1 ).

10. A control device according to claim 9 , in which said spring ( 36 , 37 ) acts on a pivotally mounted arm ( 38 , 39 ) having one end provided with a wheel ( 40 , 41 ) arranged to press against a shaped-profile rolling surface on said auxiliary shaft ( 4 ).

11. A control device according to claim 9 , in which said resultant force (F r ) has a component (F r X) which is oriented continuously towards the second item of switchgear ( 10 ) along the axis (X) along which the main drive shaft ( 2 ) moves in translation.

12. A control device according to claim 2 , in which said bore ( 8 ) has a radial orifice ( 24 ) that puts the outside atmosphere into communication with a gap between the piston ( 4 A) and the bore ( 8 ), said radial orifice ( 24 ) opening out into said gap between said sealing means ( 17 ) and the first item of switchgear ( 1 ), so that any leakage of gas (G 2 ) through the sealing means ( 17 ) is discharged to the outside atmosphere.

13. A control device according to claim 1 , in which said wall ( 7 ′) is bonded to a conductive plate ( 20 ) electrically connected to a pole of the second item of switchgear ( 10 ) and has a flexible zone in the center of which an opening is provided through which said auxiliary shaft ( 4 ) passes in leaktight manner.

14. A control device according to claim 13 , in which said auxiliary shaft ( 4 ) is provided with a piston ( 4 A, 4 A′) suitable for being moved inside a bore ( 8 , 8 ′) electrically connected to said conductive plate ( 20 ), and in which sliding contacts ( 9 ) are arranged between said piston and said bore.

15. A control device according to claim 14 , in which sealing means ( 26 ) are arranged between said piston ( 4 A) and said bore ( 8 ), and in which said other volume (V 1 ) is provided between said piston ( 4 A) and said wall ( 7 ′), the volume (V 1 ) being in communication with the outside atmosphere so as to be filled with air substantially at atmospheric pressure.

16. A control device according to claim 1 , in which said fluid (G 1 ) of said other volume (V 1 ) is a gas, and in which a safety device constituted by a valve ( 23 ) or by a breakable disk ( 46 ) makes it possible to discharge the gas (G 1 ) towards the outside atmosphere in the event that the pressure (P 1 ) of said gas exceeds a critical value.