| 摘要 |
The invention relates to a safeguard for rotatable and pivotable closures for locking a cover of manholes, vent holes and observation orifices or the like. The object on which the invention is based is to provide a safeguard for a pin which is actuable by means of a manhole key and which is surrounded by a tubular connection piece equipped with a screw cover, whilst unauthorised access to this lock is, on the one hand, to be made considerably more difficult and, on the other hand, to be designed so that the further use of the previously known closing principle and of the manhole key is ensured. This object is achieved, according to the invention, in that the safeguard is formed by a projection (14) arranged on the inner wall (6") of the tubular connection piece (6) and by a sleeve (17) which can be inserted into the tubular connection piece (6), is matched to the inner cross-section (18) of the latter and contains a lock (20), the casing (16) of which has a recess (15) for the engagement of the projection (14), behind which can engage a closing tappet (19) of the lock (20) in the sleeve (17). <IMAGE>
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