Patent ID: 6434896
Filing Date: 2002-08-20
Classification: B29C,E04H,Y02A

Abstract:
An underground tornado shelter, comprising:a dome-shaped upper half having a first flange; a hemispherical lower half having a second flange with a shape mirroring the first flange; the upper half and the lower half forming a spherical volume with a geometric center comprising: an inner wall; an outer wall, the outer wall further comprising a planar wall portion, a rib portion, and an indentation portion, the rib portion being spaced from the geometric center by a first radial distance, the planar wall portion being spaced from the geometric center by a second radial distance, and the indentation portion being spaced from the geometric center by a third distance, the first radial distance being greater than the second radial distance, the second radial distance being greater than the third radial distance; and means for connecting the first flange to the second flange.