A spring operated actuator for an electric switching apparatus including an actuator spring and a rotary air damper. The damper has components that are rotatable relative to each other and is arranged to decelerate the actuating movement during an end portion. The damper has a toroidal working chamber with internal wall surfaces formed by two circumferential housing parts. They are rotatable relative to each other and are meeting each other such that a first and a second gap are formed. There is a seal between the two housing parts, which bridges the respective gap. The seal has a first circumferential seal at the first gap and a second circumferential seal at the second gap. At least one of the first and second seals includes a sealing body fitted in a groove formed in the internal walls of at least one housing part.