Abstract: An end wall comprises a plate having a smooth, plane fromt surface whereas its rear side is stiffened by radial ribs and annular ribs. A central insertion pin is provided on the front side of the plate. Each of the four side walls of the plate is equipped with stacking bosses limiting stacking pockets which are of complementary design to the stacking bosses. When vertically aligned end walls are being stacked side-by-side or one above the other, the stacking bosses and the stacking pockets of one side wall can be joined to the complementary stacking bosses and stacking pockets of a side wall of another end wall without a joint. Corner surfaces of the end wall are rounded off and provided with cylindrical locking bosses which have the same radius as the rounded corner surfaces.

Abstract: An end wall comprises a central wall body and outer wall parts which surround and enclose the central wall part. The central wall body is of circular design and has a central insertion peg which is provided with V-shaped ridges on its peripheral surface. The outer wall parts have an inward-curving quadrant-shaped abutment surface which has the same radius as the central wall body. On the rear side of the composite plate, junctions are provided along the abutment surfaces of the outer wall parts and of the central wall body, into which junctions connecting pieces are driven. The junctions and the connecting pieces in each case have the outline of double swallowtail.At its front side, each outer wall part is provided with a locking boss which continues a rounded corner surface and has the same radius as this corner surface. The side walls of the plates are either of smooth design or provided with stacking bosses and stacking pockets.