Cap element e.g. cover, detachable fixation device for manhole, has set of nuts and cages replaced in housings by another set of nuts and cages, where nuts of sets have threaded holes with respective diameters to anchor screws

摘要

The device has fixation screws (5) to fix a cap element (4) on a peripheral inner support edge (2) of a support frame (1) of a manhole to nuts (14) arranged in housings (15) provided in the edge. Each nut is retained in a non-losable manner, in a cage (16) detachably fixed in the housing of the edge. A set of the nuts and cages is replaced in the housings by another set of the nuts and cages. The nuts of the former and latter sets have threaded holes with respective diameters, to anchor the screws with diameters different from that of the holes.