| 摘要 |
The manhole head assembly is for mounting a cover onto a manhole frame. This assembly has a lower annular rim member and an upper annular rim member. The lower member has a bottom side sized and shaped to rest on the manhole frame. It also has an opposite top side which has an inner surface portion sized and shaped to receive and support the peripheral bottom portion of the cover, and an outer surface portion. The upper annular rim member has a bottom side sized and shaped to rest onto the outer surface portion of the top side of the lower rim member in order to fully surround the peripheral edge of the cover when the same lays on the inner surface portion of the top side of the lower rim member. The upper annular rim member also has an opposite top side and a thickness substantially equal to the one of the peripheral sidewall of the cover. Bolts are used for anchoring to the manhole frame, the upper and lower rim members in operative position to receive and support the cover. Such a manhole head assembly is easy to assemble; it has a simple structure and can be vertically adjusted with one or more intermediate rim members to conform with new surface levels.
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