Shaft cast iron cover with frame resting on concrete ring

摘要

The hinged (31,32) cover (2) made of heavy, load-bearing cast iron, is enclosed in a frame (3) resting on a concrete ring (4). The frame's inner rim (16) has a raised water-drainage groove (6); its outer rim (9) has openings (10,11) matching drainage grooves (8) in the concrete ring (4). The hinges are connected to pivot bearings (34,35) positioned in holes (33) in the concrete ring, and guided by gas-pressure springs (36,37) attached to the cover and concrete ring, and sloping upwards to the cover.