LOWERING UNIT Russian patent published in 2014 - IPC E06C1/00 

FIELD: construction.

SUBSTANCE: lowering unit for arrangement of folded staircase flight includes steps, at least one guide, base; at that guides are fixed by hinges to the base. Between guide, base and steps delta-shaped tie with one changeable side is arranged; for this purpose slides are fixed in telescopic guides and by hinges the slides are also connected to the base from one side; at the other side planks are fixed to slides in order to arrange delta-shaped tie. At the corners of delta-shaped tie there is joint of the guide and base, joint of the plank and base, joint of the plank and slides. Steps have two groups of legs; one group is fixed at the step by hinge; the other is fixed rigidly; hinged legs in their turn are fixed rigidly at guides and legs with rigid connection are fixed at slides.

EFFECT: performing by the lowering unit of overlap function in folded position; expanding functionalities of the latter, providing esthetical qualities of the room.