| 摘要 |
<p>The spiral staircase has an upright column from which the steps extend in the radial direction, each resting via a support on the one below. The supports are in two parts, bearing against each other in the vertical direction by means of sloping faces. The steps are secured at each level and desired angle by clamping them to the column. One part of each support can be in the form of a right-angled triangle, one side of the right angle supporting the top step, and with recesses by which it is secured. The other is a block resting on the step below and with a sloping face bearing against the hypotenuse of the triangle. FL.</p> |
