Combined device for on-load breaking and visible isolation of an electric circuit

In a combined isolating switch-circuit breaker comprising at least one fixed contact breaking element, a fixed isolating element, at least one mobile assembly comprising a mobile contact breaking element electrically connected to a mobile isolating contact element, said two mobile contact elements being adapted for cooperation respectively with said two fixed contact elements, and means for moving the mobile assembly between an open position in which said fixed contact elements are moved apart from said mobile contact elements and a closed position in which said fixed contact elements are in electric contact with the corresponding mobile contact elements, the arrangement of said mobile contact elements with respect to said fixed contact elements as well as the nature of the movements of said mobile assembly being provided so that, when passing from the open position to the closed position said fixed isolating contact element is electrically connected to said mobile isolating contact element before the electric contact between said fixed contact breaking element and said mobile contact breaking element is established and conversely, when passing from the closed position to the open position said fixed contact breaking element is released from said mobile contact breaking element before disconnection of said fixed isolating contact element and said mobile isolating contact element, the improvement consisting in the provision of means for inserting an isolating screen between said mobile and fixed contact breaking elements in the moment following the mechanical separation of these contact elements, said insertion means comprising a setting member with accumulation of potential energy adapted for moving the screen away from the passage zone of said mobile contact breaking element, during the closure travel of the mobile assembly with, simultaneously, accumulation of potential energy and tripping means adapted for releasing this potential energy, during the opening travel of said mobile assembly, when said separation occurs so as to effect said insertion at a speed independent of that of the mobile assembly.