| 摘要 |
<p>The invention relates to a cover in the structure of a closing device of a water-supply system manhole or of a sewage system manhole. According to the invention, the cover comprises a ring (2) made by casting from a metal, inside the ring (2) there being provided a hexangle-shaped network (3) continued by some reinforcing ribs (4) attached to the ring (2), where the outer circumference (5) of the said ring (2) can have any configuration allowing it to be closed within a closing device.</p> |
