Apparatus for measuring and displaying the speed of a craft, especially of a sailboard
US4653320A · kind A · utility
Inventors
Key dates
| Filing date | Aug 21, 1985 |
| Grant date | Mar 31, 1987 |
| Priority date | — |
| Expiry date | Aug 21, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P5/07
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for measuring and displaying the speed of a craft, especially of a sailboard, comprises on one hand an immersed rotator (1) equipped with a permanent magnet and attached to the craft (40) and on the other hand a measuring device mounted on the craft. The measuring device comprises a coil having a very large number of turns, at least one operational amplifier and a frequency meter for determining the frequency of rotation of the magnetic field produced by the magnet of the rotator (1). A sealed box (30) encloses the entire measuring device, its liquid crystal display unit and photovoltaic cells for its power supply. The apparatus is particularly adapted to be removably mounted on a sailboard or a light dinghy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.