Spiral stairlifts
Screw, or spiral ladders are applied, when there is not enough place for straight ladders. Spiral staircases are less convenient for movement, than straight lines, but they allow saving the area of a premise and they are often applied as auxiliary to rise or descent in a ground floor. Basic feature screw relies in fastening steps around of a column, or racks. Steps of a spiral staircase are of cuneated forms and are being located around of this central rack. More often it is carried out in the form of a metal pipe. The narrow party of steps fastens to a rack, and wide more often - to rail posts or to walls. Stair riser, as a rule, is absent - the step fastens to a rack of a handrail by its wide end. In order that the leg would feel comfortably on the step, the central width should make not less than 200-250 mm and no more than 400 mm in its widest part.
Thus the form of a spiral staircase contrary to traditional representation about it can be not only round, but also square, octagonal etc.
Spiral staircases are more often made of metal or tree. So, it is possible to create an original interior and spiral staircases can be settled down not only at a bearing wall, but also in the center of the room.
Though spiral staircases take not so much place, they are used less often than rectilinear. The matter is that they are not so convenient. Descent on them demands attention and care. And consequently the preference is more often given to mid-flight analogue. Basically “screw” is used as an auxiliary variant (because the main smart ladder in the house is always mid-flight). Besides, screw stair lifts are used, when the aperture for installation of a ladder is too small. Though there are big spiral staircases - up to 3 meters in diameter. However, experts consider that in an aperture of such size it is more reasonable to choose a mid-flight ladder. It is defined with the whole complex of components. The ladder is designed under the concrete house. The optimality of its parameters also creates comfortableness of rises and descents. The height of a step can vary from 15 up to 19 centimeters, and height of a hand-rail should make 90-95 centimeters.????
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