Form for manholes and the like

Claim 1

A form for manholes or the like comprising, when assembled, an inner shell and an outer shell, said inner shell extending to the full height of the structure being formed and including a plurality of vertically stacked sections, each inner shell section comprising a plurality of individual rigid panels edge interlocked to define a generally cylindrical configuration, said panels being selectively releasable from the adjoining panels for removal, said outer shell including a plurality of vertically stacked sections corresponding in number and height to the inner sections, each outer section being formed into a generally cylindrical configuration, the generally cylindrical configuration of each outer shell section being of a greater internal diameter than the corresponding inner shell section and being positioned thereabout in circumferential outwardly spaced relation thereto to define an internal forming area, each inner shell panel including reinforcing members welded thereto completely about the periphery thereof and defining inwardly projecting securing flanges completely about each panel, each outer shell section being formed of a single continuous member peripherally reinforced completely thereabout by reinforcing which defines outwardly projecting peripheral mounting flanges including a pair of vertical end flanges boltable together to form the outer shell section into a cylindrical configuration surrounding the inner shell, both the inner shell and the outer shell including a base section, a middle section and an upper cone section releasably interlocked to each other, the panels of each inner shell section including a key panel for facilitating both a positioning and removal of the panels of the section, said key panel including opposed vertical edges with the edge reinforcing thereon projecting parallel to both each other and a center line which bisects the key panel and the circular configuration defined by the section, the adjacent edge reinforcing on the two panels which adjoin the key panel of the section being similarly orientated so as to abut along the key panel vertical edge reinforcing along the full length thereof whereby a direct inward withdrawal of the key panel can be effected as an initial step in the disassembly of the inner shell section, the vertical edge reinforcing on the remaining panels of each section, as well as the opposed vertical edges of the two adjoining panels, being radially directed relative to the cIrcular configuration defined by the section.