Dual stereographic net
OwnerChristopher M. Powellinventor
Life of this patent
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Abstract
Instruments presently available for stereographic calculations use a single net over which transparent paper is moved. The device of this invention has two nets, one printed on each side of a rotatable disc in a frame and the calculations are made by rotating the nets under transparent paper fixed to the frame.
Claims1
An instrument for making three-dimensional angular calculations in two dimensions by means of a circular base comprising a circular disc rotatable in a frame, the frame comprising two flat surfaces and four sides and being cut-away on at least one side to expose the edge of the disc to enable it to be rotated, the frame also having a cut-away on each of its flat surfaces to expose the central area of each side of the disc, an equal-angle stereographic net on one exposed central area of the disc, an equal-area stereographic net on the other side exposed central area of the disc, and degrees marked round the cut-away on each of the flat surfaces of the frame, the calculations being made on a transparent overlay fixed to the outside of the frame.
Dependencies are inferred from the claim text.