| 摘要 |
A moulded plastic inspection cover or manhole lid for underground services such as electrical cables or wires , telephone and video communications fibres, or traffic signals, cast or formed in one homogenous piece with a continuous top section with a moulded pattern and a continuous or semi-continuous bottom section formed by plurality of intersecting vertical webs in longitudinal, transverse and diagonal alignments, and side edge cavities on all or some sides. The cover is generally rectangular or circular in shape. A centralised load on the cover is transferred to the reinforced peripheral edge or rim via the intersecting ribs. An alternative form has the side cavities extending to the centre of the lid forming a top and bottom sheet or plate or skin with connecting webs. The cover can be locked or securely fastened to a supporting socket or ring.
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