ACCESS COVERS FOR MANHOLES

摘要

The access cover is of the kind comprising a cover member removably fitted within a generally rectangular outer frame, the cover member being fabricated as a generally rectangular inner frame (13) fixed to a base plate (11), the space formed thereby being subsequently filled with an appropriate filling material. The invention is characterised by a reinforcement arrangement provided for the inner frame (13) comprising a number of bars (8) fixed to the base plate (11) of said inner frame, and each bar comprising sheet material (1) formed into a channel shaped cross section. Conveniently, each bar (8) comprises a bottom web (3) incorporating a line of spaced fixing means (2) for attachment to the base plate (11) and opposed walls (6, 7) which taper outwardly from said web. Preferably, the bars extend parallel to each other and the base plate (11) is provided with respective parallel lines of spaced fixing means (12) for co-operating and interlocking with said fixing means (2) of the bars (8). Preferably, said fixing means (2, 12) comprise a spaced line of co-operating tongues (12) and cut-outs (2) for each bar, the arrangement being such that each bar is interlocked onto the base plate (11) by aligning the co-operating cut-outs and tongues and sliding movement from a side of said base plate. The invention is an improvement to the reinforcement arrangement used hitherto, enabling an extremely strong and rigid cover member to be produced.