| 摘要 |
A height adjustment manhole which is convenient, height-adjustable on site and free from time loss, economic loss, and traffic and safety problems which would otherwise be incurred by a subsequent and recurring construction work for a manhole and its surrounding involving a road breaking-up work and continuing after a road repair or other work, comprising an upper pipe and a separate lower pipe fixed underground, wherein the height of the upper pipe is fixed by allowing an adjusting device projecting from the upper pipe and adapted to be vertically adjustable according to the height of the road surface to engage another adjusting device projecting in three stages from the lower pipe. In a second embodiment, the cylindrical projection of the lower pipe goes into the oval adjusting port engraved in three stages in the upper pipe to keep a specified height. When closing an upper cover, a projection (Fig. 1-2) at the lower portion of the cover is set in a gap made in a cover fixing device (Fig. 1-4) provided at the inner peripheral edge of the upper pipe and is turned slightly to lock the cover.
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