| 摘要 |
<p>A manhole cover and frame assembly includes an outer frame having a support surface and a side wall that extends upward from the support surface and has a recessed portion. An inner frame is supportable on the support surface. The inner frame has a protrusion extending from the outer peripheral surface. The inner frame also includes an adjustable joint for adjusting the inner frame in its peripheral dimensions to expand to engage the protrusion with the recessed portion, thereby preventing upward movement of the inner frame, and to contract to remove the protrusion from the recessed portion. The inner frame also includes a cover support surface. A manhole cover is supportable on the cover support surface.</p> |
