Actuation unit for a switching apparatus

An actuation unit for a switching apparatus,

• wherein said actuation unit is configured to actuate one or more movable contacts of said switching apparatus during a closing maneuver and an opening maneuver of said switching apparatus,
• wherein said actuation unit comprises:
• a contact shaft coupled to the one or more movable contacts of said switching apparatus and reversibly movable about a corresponding first rotation axis;
• and
• first mechanical actuation means coupled to said contact shaft and configured to actuate said contact shaft during a closing maneuver of said switching apparatus,
• wherein said first mechanical actuation means comprise:
• a spring assembly including one or more spring elements, wherein said spring assembly is configured to take reversibly a loaded condition, at which said spring elements are loaded and store mechanical energy, and a released condition, at which said spring elements have released the stored mechanical energy;
• and
• a kinematic chain coupling said spring assembly to said contact shaft, said kinematic chain including a first lever member movable about a second rotation axis parallel to said first rotation axis and coupled to said spring assembly, wherein said first lever member is configured to move reversibly between a first position, which corresponds to said loaded condition of said spring assembly, and a second position, which corresponds to said released condition of said spring assembly,
• wherein said actuation unit further comprises mechanical loading means configured to actuate said first lever member and said spring assembly in order to make said spring assembly pass from said released condition to said loaded condition,
• wherein said mechanical loading means comprise a cam assembly movable about a third rotation axis parallel to said first rotation axis and including one or more cam members, each cam member having a cam surface couplable to said first lever member,
• wherein said cam assembly is configured to move reversibly between a third position, which corresponds to said first position of said first lever member, and a fourth position, which corresponds to said second position of said first lever member,
• wherein said actuation unit comprises, for at least a cam member of said cam assembly, a brake member configured to brake said cam assembly, and
• wherein each brake member is in a fixed position relative to a corresponding cam member and has a sliding surface configured to come into frictional contact with the cam surface of a corresponding cam member, during a rotation movement of said cam assembly from said third position to said fourth position, a mechanical interaction between the sliding surface of each brake member and the cam surface of the corresponding cam member causing a reduction of a rotational speed of said cam assembly.