Operating mechanism of a three-position switch

An operating mechanism of a multipole switch having a movable assembly capable of occupying three distinct stable positions, notably a first closed position (F), a second intermediate open position (O), and a third grounded position (T), said mechanism (10) comprising:

• an energy storage spring (12) associated with a toggle (16) having a high-speed dead-point overshoot, the toggle (16) beign fitted with an actuating lever (18) articulated on a spindle (20) of a first operating crank (22) for changing a line of action of said energy storage spring (12),
• a main operating crank (26) fixed on a rotating shaft (28) which actuates the movable assembly of the switch,
• a grounding crank (38) mounted with limited rotation on a first operating spindle (52) between an inactive position when the main crank (26) is moved by the toggle (16) between the closed (F) and open (O) positions, and an active grounded position causing the line of action of the energy storage spring (12) to be modified resulting in further rotation of the main crank (26) beyond the open position (O) to the grounded position (T),
• a second operating spindle (62) for controlling opening and closing of the switch, said spindle (62) being offset from the rotating shaft (28) and cooperating with a transmission system (64) capable of driving the first operating crank (22) of the toggle (16) in rotation, and
• locking means for locking the main crank 26 in each of three positions (F, O, T) of the switch, said locking means including a latching lever (78) cooperating with the main crank (26), said lever being automatically actuated to an unlocked position when the toggle (16) is near the dead-point.