Heliochron
US4890269A · kind A · utility
Inventors
Key dates
| Filing date | Aug 7, 1989 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Aug 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04B49/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A helichron having a box-like housing to which a cover is pivotally hinged. A magnetic compass is positioned in the box-like housing at a predetermined directional orientation. A 360 degree spirit level is also positioned within the box-like housing. The top surface of the cover has an hour scale recess having a semi-circular wall portion and a planar surface portion. An Arabic numbers hour scale is imprinted on the semi-circular wall to denote hours for the northern hemisphere and a Roman numeral hour scale is imprinted on the horizontal planar surface to denote hours for the southern hemisphere. There is a gnomon and structure for mounting its bottom end in the horizontal planar surface of the hour scale recess. There is also a latitude scale member attached to the bottom surface of the cover whose index is set to the users latitude by varying the angle of the cover.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.