| 摘要 |
PURPOSE:To make it possible to constitute a staircase at a low cost without lowering bearing strength and design efficiency in appearance of a stair string bearing a tread on both sides thereof. CONSTITUTION:A stair string bearing treads 10 on both sides thereof is constituted separately of a holding plate 20 actually bearing load applied to the tread and a facing side plate 30 to which load is not applied while exposing it upward of the tread 10. The holding plate 20 is not necessary to consider its design efficiency, but it considers only its strength to serve to set its thickness, etc. The facing side plate 30 is not necessary at all to consider such strength as the thickness, etc., so that, as a whole, the stair string can be formed at a low cost in comparison with the whole stair string formed of an integral wood plate, etc. |
