Actuator and corresponding method

An actuating drive (1), comprising:

• a motor (2);
• an output (4) which is driveable by the motor (2) and is couplable to a fitting;
• an emergency drive (5) with an energy store (6), by which the output (4) is driveable as an alternative to the motor (2),
• the energy store (6) being a pneumatic energy store (7);
• the energy store (6) including a pressure chamber (8) with an expandable volume;
• wherein, during operation of the emergency drive, an expansion movement of the pressure chamber (8) is conducted to the output (4);
• the energy store (6) is loaded by the motor (2) by actuation of the motor (2) after an end position of the actuating drive (1) is reached;
• and
• the emergency drive (5) and the motor (2) are coupled to one another such that at least one of torques or forces which are generated in each case are superimposed at the output (4).