| 摘要 |
<p>A stair step of the plate-shaped step type comprises plate members bent downwards from the stepping surface at all four rims. The plate members are welded together at the corners where they abut one another. The plate members at the front and rear rims are rolled over to form cylindrical pipes, such that the plate member at the front rim is rounded at the bottom, thereby preventing jamming of the foot between the steps. The cylindrical pipes are filled with a foamed insulating material, such as polyurethane foam.</p> |
