Beam body with part expandable across beam in longitudinal direction - has centre of three parallel rows of apertures bridging over those in outer rows

摘要

The beam body has three parallel rows of slot-shaped apertures (16, 17, 18). The apertures in the outer rows (16, 17) are positioned centrally to one another, with the apertures of the intermediate row (18) being so positioned that the bridge over the distance between the apertures of the outer rows and extend in between them. In this way, a body structure is formed between the aperture of the outer rows which has the form of of a recumbent H. The arms (19) the H are curved.