Curtain door alarm
US5777552A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1995 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Aug 2, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A magnetic alarm sensor (80) includes a magnet (84) positioned so that dominant length components (108) of its magnetic field lines (104) are oriented so that they are transverse to a switch axis (96) of a magnetically sensitive switch (88). This orientation permits more versatile mounting options for placement of the alarm sensor, especially to positions that are less prone to displacements over time. A preferred embodiment of the magnetic alarm sensor (110) employs two spatially collinear magnetic switches (116, 118) vertically oriented along a door bracket (14) and a magnet (120) positioned on a door panel (22) such that the magnetic field lines (152) of the magnet are generally perpendicular to the switch axis (136) of the magnetic switches. The magnetic switches are electrically connected in parallel to extend the range of vertical critical distance between the magnet and the magnetic switches to inhibit false alarms caused by door sag.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.