| 摘要 |
<p>A lid assembly comprises a reception frame (20) installed on a facility access opening, a round lid body (10) fitted in the reception frame, the reception frame having in its top an inner peripheral surface (20b) in the form of an S-shaped curved surface having a convex surface portion (21) and a concave surface portion (22) formed thereabove to extend therefrom, the lid body having a peripheral surface (10b) in the form of an S-shaped curved surface substantially complementary to the inner peripheral surface in the form of an S-shaped curved surface in the reception frame. When the access opening is closed by the lid body, the lid body is smoothly fitted in the reception frame by the guide function of the inner peripheral surface in the form of an S-shaped curved surface in the reception frame.</p> |
