| 摘要 |
1. A polygonal, particularly rectangular, frame for man-hole covers assembled from a number of frame members (1, 2, 3, 4) extending lengthwise of the frame sides, the frame members being provided with supporting and/or inclined sealing faces for a cover, at least two opposed frame members (1, 3) being identical, characterized in that one pair of opposed frame members (1, 3) is interchangeable after turning it by 180 degrees about an axis (X) extending parallel with the frame plane, and in that the other pair of opposed frame members (2, 4) is interchangeable after turning it by 180 degrees about an axis (Y) parallel with the frame plane and rotating it about an axis (Z) normal to the frame plane. |
