| 摘要 |
<p>The covering (1) has a cover (3) arranged on a frame with fastening units for fastening the frame to a ground and comprising a centrically arranged convex projection, where the covering is made from fiber-reinforced plastic. A cylinder-shaped ventilation piece (4) is arranged in the center of the projection, where an edge of the cover completely covers the frame and the fastening units and corresponds to an edge of the frame. The ventilation piece has a hole in an area of an upper end, where an upper side of the ventilation piece is closed with a downwardly-aligned flange-like covering (10).</p> |
