Demagnetizing apparatus for use in vehicles
US4378581A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1981 |
| Grant date | Mar 29, 1983 |
| Priority date | — |
| Expiry date | May 26, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F13/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A demagnetizing apparatus for removing residual magnetism in the body of an automobile which is equipped with a magnetic bearing indicator. A first and a second coil are wound around a substantially flat frame of a non-magnetic material to produce respectively a fixed d.c. magnetic field and a controllable a.c. magnetic field in orthogonal directions with each other and along flat surfaces of the substantially flat frame. The substantially flat frame with coils is positioned adjacent to but spaced from a body portion such as a roof, door or floor of the automobile, so that the d.c. magnetic field produced by the first coil cancel the external magnetic field caused by the terrestrial magnetism. The a.c. magnetic field is controlled to be intensified and weakened alternately thereby to remove the residual magnetism of the body portion without being influenced by the external magnetic field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.