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US5060390A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 29, 1990 |
| Grant date | Oct 29, 1991 |
| Priority date | — |
| Expiry date | Jan 29, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C21/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A navigation device is disclosed, having a lens across an opening at one end of a case, and a compass across an opening at the opposite end of the case. A transparency holder is positioned between the lens and the compass, adapted to receive a map transparency with magnetic north thereon aligning with a north marking on the body of the compass, at a distance from the lens approximating the focal length of the lens. A grid wheel is provided between the transparency holder and the compass, having a transparent or translucent central area inscribed with parallel grid lines and at least one first directional arrow aligned parallel to the grid lines, the grid wheel being in close proximity to the transparency holder such that it is also at a distance from the lens approximating the focal length of the lens. Positioned between the grid wheel and the compass, and geared to the grid wheel for counter-rotation therewith, is a direction wheel having a transparent or translucent central area inscribed with at least one second directional arrow. A bearing may thus be taken by examining an installed map transparency through the lens, rotating the grid wheel and direction wheel to align the grid…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.