Together to ensure the operational safety of the In the United States Patent manhole, it is not necessary to divide such as the frame even when put the hose into the manhole, and further, even if there is a reverse injection of water and sludge, ambient to provide a safe guard for manhole work that does not contaminate the. A circular frame constructed around A manhole from ground to surround a predetermined height, a portion of the circular frame, toward the bottom surface side from the top surface side leaving a portion of the bottom side and the hose opening notched, and a lid portion in which the mounted openably on the top surface of the circular frame, attached to the lid portion, which can be hidden and closing the lid covering the hose opening rubber and sheet, with a safety guard for manhole work, characterized in that. .FIELD 4
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