US Patent 7091439 Isolator/circuit-breaker device for electric substations

An electric device, in particular for medium or high voltage electric substations, able to perform the functions of circuit-breaking, isolating and earthing is described. The device comprises: a casing; at least one circuit-breaker; at least one line isolator having a fixed isolator contact; a line isolator actuating shaft for actuating the at least one line isolator; at least one earthing isolator; a circuit-breaker actuating shaft for actuating at least one circuit-breaker; and a lever connected to a conductor rod co-operating with movable circuit-breaker contacts, said conductor rod further engaging with said fixed isolator contact in a closing position, wherein: the device further comprises a resilient member co-operating with said conductor rod in order to transfer correct pressing loads to said movable contacts. According to the invention, said circuit-breaker actuating shaft and said line isolator actuating shaft are coaxial. Profitably, the casing is filled with nitrogen or sulphur hexafluoride.