| 摘要 |
A design for manhole frames is provided which provide one or more handholds near the entrance to the manhole so that the ladder rungs can be made lower and the access space at the entrance to the manhole thereby increased. The handhold can be cast into the cover- supporting lip, or can be a movable handle which is below the level of the manhole when not in use or extended above ground level when in use. |
