FIELD: mechanical engineering. SUBSTANCE: construction has reinforcing member with stop-bearing surface from the one end and with projection from the other one. The projection has rounded surface which is defined by locking part from the one side. The part can be received below of one of the shelves by rotating about the axis parallel to the shaped member and serves for defining localized deformation of the shelf at the part provided with projection extension and locking part, which engages the other shelf from bellow, from the other side. When the projection is in the interlocking position, it bears on the bottom of mounting place at least at two points which are spaced in the lateral direction with respect to the shaped member. EFFECT: enhanced reliability. 4 cl, 10 dwg
