| 摘要 |
A raising band for use in a manhole, which is both waterproof and very easy and non-costly to construct, thus rendering it easily adjustable as the need arises whatever be the height of the layer of asphalt that is adds to the road surface. It includes an upper ring of metal dimensioned to receive the cover of the manhole and a lower ring, also of metal, dimensioned to be inserted into the recess provided for receiving the cover of the manhole frame. These two rings are joined by a cylindrical sleeve made of metal, which is welded to them all along the length of its upper and lower edges.
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