Charger for hand-held rechargeable electric apparatus with reduced magnetic field
US5680028A · kind A · utility
Inventor
Key dates
| Filing date | Sep 21, 1994 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | Sep 21, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S336/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved system for charging a battery of a hand held device, such as an electric toothbrush. The system has a first coil coupled around a first magnetic core. The first magnetic core forms a substantially closed magnetic path except for a core gap. An AC power signal is applied to the first coil to create a varying magnetic field within the core gap. The core gap is configured to minimize radiation of magnetic flux whether the second magnetic core is in place or not by having its faces closely spaced and aligned substantially parallel to one another. A second coil is coupled around a second magnetic core. The second magnetic core is insertable into the core gap to form an AC current in the second coil. The second magnetic core is sized to substantially occupy the core gap to minimize radiation of magnetic flux. The size of the gap and the length of the second magnetic core are made as small as possible to keep the weight of the hand-held device low. The second coil is coupled to a rectifier which is in turn coupled to charge the battery.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.