Equatorial sundial
OwnerTimothy E. Doyleinventor
Life of this patent
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Abstract
An equatorial sundial according to this invention includes a dial surface and an elongated, rod-like gnomon fixedly secured in operative relation thereto. The dial surface is generally semi-cylindrical and concave toward the sun. The circumferential portion of the surface is further formed in the shape of a partial helix. The gnomon lies on the axis of the dial surface such that the longitudinal extent of the surface is transverse of the gnomon at an obtuse angle thereto. In a given geographical location, the sundial is so oriented relative to the earth that the gnomon is parallel to the earth's axis of rotation. With a proper pitch of the helical form of the dial surface, the opposite end portions thereof are offset in a direction parallel to the axis of the gnomon so that neither shade the dial surface either in the morning or evening.
Claims14
A sundial comprising a dial surface and an elongated, rod-like gnomon fixedly secured in operative relation thereto, said surface having an upward curvature outwardly from the central portion as developed from a flat plane about a given axis, said gnomon paralleling said axis, said surface between its ends extending transversely of said gnomon at an obtuse angle therewith, whereby the opposite end portions of said surface are offset in a direction parallel to said axis, and spaced time lines on said surface parallel to said axis.
Dependencies are inferred from the claim text.