초록 ▼

A riser formed from a plurality of curved cylindrical segments with vertical side edges having mating vertically tapered projections and slots brought into interlocking engagement to pull confronting surfaces together as the tapered elements become increasingly mechanically engaged. The segments are

A riser formed from a plurality of curved cylindrical segments with vertical side edges having mating vertically tapered projections and slots brought into interlocking engagement to pull confronting surfaces together as the tapered elements become increasingly mechanically engaged. The segments are assembled by a sliding engagement of the protruding mating element of one segment into the vertically tapered slot of an adjacent segment. When sufficient segments are joined together horizontally to complete a ring except for a last adjacent pair of vertical side edges, the ring is warped to align the protruding mating element of the last adjacent pair of vertical side edges with an opposite end of the adjacent tapered slot. Thus aligned, the final protruding mating element and tapered slot are then slipped together while un-warping the joined segments forming the remainder of the ring until the top and bottom ends of all the segments are aligned. A cover has a flexible spider on a lower surface that can be locked into a groove or other feature on an inside surface of the curved riser segments.

대표청구항 ▼

The invention claimed is: 1. A method of assembling a subterranean structure from a plurality of segments, each segment formed of a wall element cylindrically curved about a vertical axis having an inside surface and an outside surface, vertical side edges and horizontal top and bottom ends, a first

The invention claimed is: 1. A method of assembling a subterranean structure from a plurality of segments, each segment formed of a wall element cylindrically curved about a vertical axis having an inside surface and an outside surface, vertical side edges and horizontal top and bottom ends, a first of the vertical side edges including a protruding mating element that is vertically tapered, and a second of the vertical side edges including a slot that is vertically tapered, the method including the steps of:sliding a protruding mating element of one segment into the vertically tapered slot of an adjacent segment until the top and bottom ends of the adjacent segments are aligned,repeating the sliding step with additional segments until sufficient segments are joined together horizontally to complete a ring except for a last adjacent pair of vertical side edges,warping the joined segments by a distance sufficient to align the protruding mating element and tapered slot of the last pair of vertical side edges, andengaging the mating portions of the last pair of vertical side edges while un-warping the joined segments until the top and bottom ends of all the segments are aligned to complete the ring so that the vertical side edges including confronting surfaces are brought into abutting relationship solely by the interlocking engagement between the vertically tapered mating elements and vertically tapered slots on the horizontally adjacent segments.