Apparatus for securing the position and attachment of a circular cover or diffusion plate in an annular retaining part, in particular for lamp body

Apparatus for securing the position and attachment of a circular cover or lens (11) in an annular retaining part (1), in particular for lamp body, wherein the holding part (1) on its underside at least partially the inner circumference extending stop edge (10), less the diameter of which as the clear inside diameter of the top is to thereby form a support for the to be inserted from the top plate (11), characterized in that the circular disc (11) has two opposite cutouts (12) in the form of parallel secants, further on the holding part (1) has two with respect to the disc cut-outs (12) complementary projections (4) are formed in the direction of the circular ring center, wherein between the stop edge (10) and the projections (4) towards the top of the holding part (1) a distance at least corresponding to the thickness of the disc (11) is present to bezugl by relative rotational movement I inserted disc (11) and holding part (1) to effect a positive lock between them.