Drive device for a power switch

A drive device for a power switch, for medium or high voltage, having a cam disk which, for switching on the power switch, is driven by means of an energy store about an axis in a direction of rotation and which comprises a curved path which includes a first section of a radius which increases as the azimuth increases counter to the direction of rotation, and a second section which follows behind the first section in the direction of rotation and runs roughly in the radial direction, having a follow-up member which is forced by a disconnecting spring in the direction of the cam disk and which by rotation of the cam disk in the direction of rotation by means of the first section of the curved path is moved from a switch-off setting, as the disconnecting spring is simultaneously tensioned, into a switch-on setting by a measure of overtravel, and which is designed to be connected to a movable contact piece of the power switch, and having a pawl for releasably supporting the follow-up member in the switch-on setting after the first section has run off from the follow-up member, wherein the curved path exhibits, in the direction of rotation, between the trailing end of the first section and the second section, an intermediate section of a radius which becomes steadily smaller as the azimuth increases, against which intermediate section the follow-up member bears until supported against the pawl,

• wherein the energy store comprises a connecting spring connected to a first end of a traction element, which, eccentrically attached in an articulated manner by a second end thereof to the axis of the cam disk, is connected to the cam disk, and the trailing end of the first section of the curved path interacts with the follow-up member whenever the articulated attachment of the traction means is located at least approximately in a stable dead center position, a reduction in the radius of the curved path in the intermediate section is larger than the overtravel, the intermediate section comprises an angle of 10.degree. to 20.degree., and the reduction in the radius of the curved path in the intermediate section measures 0.2 to 5% of the difference between the largest and smallest radius of the first section.