Manhole cover with adjustable levelling steps - has frames with stepped blocks for vertical adjustment, in discrete steps

摘要

The manhole cover level can be adjusted for installation into road surface, the cover and its frame being made by casting without subsequent machining. The manhole cover frame has a circular upper frame mounted on a supporting frame with stepped height adjustment features. The upper frame height is adjusted by rotation in relation to the lower frame and the height in discrete steps. On the upper frame (1) and on the lower frame (2) are arranged complementary blocks with steps (5, a, b, c). These stepped features are arranged on the circumference so that at each angular position of the upper frame the upper and lower steps are in firm contact for providing support for the manhole cover which can accommodate weights of heavy vehicles.