Pole operating device in a medium-voltage electric control apparatus

The present invention relates to a device D for controlling the poles of an electric protective apparatus capable of driving a shaft (1), called the first shaft, for supporting the movable contacts between an open position of the pole in which the movable contacts and the fixed contacts of the apparatus are separated and a closed position of the pole in which these movable and fixed contacts are closed, the said device D comprising a closure spring (2) controlled by an operating shaft (3), called the second shaft, the said spring (2) being capable of transmitting closure energy to the said shaft called the first shaft (1) after compression and passing of the said spring (2) beyond a neutral point line of passage, by means of a cam (8) rotated by the said shaft called the second shaft (3), and interacting with a roller (5) secured to the shaft called the first shaft (1), means (13) for holding the control shaft called the first shaft in the closed position, and means (18, 5) for unlocking the aforementioned holding means (13) allowing the rapid opening of the contacts of the apparatus, this device being characterized in that the aforementioned holding means (13) are supported by the said cam (7, 8).