| 摘要 |
A modular, self supporting flight of stairs, comprising at least one pair of stringer units for supporting at least one step thread. Each stringer unit comprises a vertical side plate provided with an horizontal, upper flange and a vertical front plate defining with the side plate, a rectangular dihedron. This front plate is also provided with an horizontal, upper flange defining together with the upper flange of the side plate, a rigid, L-shaped support very stable in use for supporting one end of the thread. Each stringer unit also comprises a small, fixation plate integrally extending the side plate in the same plane as, or in a plane parallel to, the plane of the side plate. The stringer units of each pair are fixed to the corresponding units of a pair immediately superior or inferior thereto by riveting or bolting the fixation plates of one pair to the side plate of the other pair through a plurality of holes punched fixation plate and the lateral plate of the stringer units for receiving the bolts. This flight of stairs is particularly interesting because it has an excellent lateral stability due to the presence of the stabilizing front plates of each pair of stringer units on the upper flanges of which is fixed each thread, and because it also may support a very heavy load due to the punched holes used for riveting or bolting the stringer units together, the punching indeed providing some engagement of the holes one inside the other during the riveting or bolting step and thus ensuring an improved reinforcement of the flight against any vertical shearing force. |
