The plastic body has a locating surface with through passage apertures for fixture of the first housing lying in one plane. On the body is formed, also lying in one plane, a further surface locating on the second housing. The shell-shaped one-piece plastic basic body is produced by injection molding with support ribs (9) inside the shell. In the body vertical to the surface locatable on the second housing bushes (4) are formed. Through passage apertures (8) are formed in a flange-type edge area (7a) of the basic body. The bushes are embedded with minus tolerance in the screw head-side locating surface (4a), which are formed as metal cylinder bushes.
