Wide gap magnetic reed switch and method for manufacture of same
US4943791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1989 |
| Grant date | Jul 24, 1990 |
| Priority date | — |
| Expiry date | Jan 25, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H36/0026
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A magnetically actuated reed switch assembly in which a small permanent helper magnet is attached to a magnetic lead of the reed switch at an end of the reed switch envelope. The lead then may be bent around parallel with a magnetic reed of an encapsulated reed switch. The permanent helper magnet provides an axis of magnetic polarity parallel with the axis of the reed switch, and is magnetized to a level of magnetism which supplies slightly less than enough magnetic flux density to hold the reed switch in a magnetically actuated condition, so that only a small amount of additional flux density needs to be provided. By selecting reed switches within close tolerances and using helper magnets of selected size and strength within close tolerances, satisfactory assemblies may be produced without adjustment of helper magnet position to actuate the switch. The small permanent magnet may alternatively define a bore fitting around the magnetic lead, and may be magnetized after assembly of the magnet and magnetic lead of the switch, thus reducing the amount of time and labor required to manufacture the switch assembly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.