| 摘要 |
The present invention relates to a manhole cover comprising a surrounding frame (1) having the form of a rectangular quadrangle and a lid section adapted to selectively hold a closed position in which it closes the frame (1) and an open position in which it opens a free passage through the frame (1). The lid section comprises at least one pair of triangular plates (2, 3; 12, 13) hinged to one of the adjoining sides of the frame (1). One of said triangular plates (2, 3) is provided with at least one support (5) projecting from the hypotenuse (4) thereof and cooperating with bottom surface of the adjacent second plate (3, 2), in closed position of the lid section. |
