| 摘要 |
<p>The step tread panels are attached to a carrier underneath them, which is fastened to the central stringer of the staircase. The tread panel carrier (4) is spherical in its centre on the side facing away from the panel (5), with an opening (10'), in the centre. A support (3) has a correspondingly shaped counter face on an end fitting against spherical surface, so that the two surfaces combine to form a ball-and-socket joint. The carrier may be arched outward in a convex shape on the underside.</p> |
