Proximity switch with three switching positions
US5578977A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 20, 1995 |
| Grant date | Nov 26, 1996 |
| Priority date | — |
| Expiry date | Sep 20, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE05B17/22
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A microswitch with an integrated circuit includes a ferromagnetic tripping body being movable between three switching positions. Two Hall sensors are associated with the tripping body. A permanent magnet being disposed fixedly below the two Hall sensors has one pole facing toward the two Hall sensors for generating field lines penetrating the Hall sensors. A dual evaluation circuit ascertains a ratio of magnetic flux in each of the two Hall sensors, derives a switching signal from a change in the ratio upon an approach of the tripping body and has first and second outputs. The dual evaluation circuit changes a switching state with respect to one of the outputs in reaction to a positive or negative difference in magnetic flux between the two Hall sensors. In this way, an occurrence of a vanishingly small difference, a positive difference and a negative difference in magnetic flux is switched through the three positions of the tripping body.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.