Abstract: A device for controlling a central shutter, in which a plurality of shutter leaves (3) are mounted on a circularly annular leaf carrier (1) such that they can be pivoted on a pivoting arm (4), and in which, as actuating device for the pivoting movement of the shutter leaves (3), an annular cam plate (5) is mounted on the leaf carrier (1) concentrically with respect to the shutter opening (2), such that it can be rotated continuously in one direction, it being possible for the rotation of the cam plate (5) to be blocked by mechanical engagement into a cam trough (8) in front of an actuating flank (6) of a cam, is distinguished by the fact that, for mechanical blocking purposes, there is a push rod (9, 10) of a solenoid, which push rod (9, 10) can be moved perpendicularly with respect to the plane of the cam plate (5).

Abstract: A device for controlling a central shutter, in which a plurality of shutter leaves (3) are mounted on a circularly annular leaf carrier (1) such that they can be pivoted on a pivoting arm (4), and in which, as actuating device for the pivoting movement of the shutter leaves (3), an annular cam plate (5) is mounted on the leaf carrier (1) concentrically with respect to the shutter opening (2), such that it can be rotated continuously in one direction, it being possible for the rotation of the cam plate (5) to be blocked by mechanical engagement into a cam trough (8) in front of an actuating flank (6) of a cam, is distinguished by the fact that, for mechanical blocking purposes, there is a push rod (9, 10) of a solenoid, which push rod (9, 10) can be moved perpendicularly with respect to the plane of the cam plate (5).

Abstract: A releasable and stress-free securing assembly for an optical element (2, 3) positioned in a centered manner in a mount (1) is provided. The optical element (2, 3) is provided, in the border region which is to be retained, with a beveled surface (6) inclined in the direction of the mount (1). The mount (1) has a groove (4) which is open axially in front of the optical element (2, 3). A ring element (5) which is elastically deformable in the axial direction is pressed in between the beveled surface (6) and groove (4). The angle of inclination of the beveled surface (6) is between 40° and 50°. The boundary (11′) of the groove (4) in the region of the optical element (2, 3) is level with a bevel edge (8), which is oriented toward the mount (1), and the boundary (11) of the groove (4) in front of the optical element (2, 3) is undercut at an angle of from 10° to 15°. The depth of the groove (4) is greater than the radius of the ring element (5) by from 0.15 to 0.