| 摘要 |
The device will be used at the construction of sewer shafts within the scope of settlements' streets. The device consists of a ring (3) with protruding aside two ribs (5), and a ring (2), which ringsare connected by a greased thread. In the structure of the ring (3) there are two openings (4) used for rotating ring (3) around ring (2) by a metal lever, until the necessary height is reached. Thisheight is fixed by the lid (1).
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