Multi-phase mode multiple coil distance deactivator for magnetomechanical EAS markers
US5867101A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1997 |
| Grant date | Feb 2, 1999 |
| Priority date | — |
| Expiry date | Feb 3, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2411
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A device for deactivating a magnetomechanical electronic article surveillance marker includes first, second, third and fourth rectangular coils arranged in a two-by-two array in a common plane. Drive circuitry energizes the coils according to an operating cycle which includes three modes. In the first mode, all four coils are driven with respective alternating currents in phase with each other. In the second mode, the first and second coils are driven in phase with each other and the third and fourth coils are driven substantially in phase with each other and substantially 180.degree. out of phase with the first and second coils. In the third mode, the first and third coils are driven in phase with each other and the second and fourth coils are driven in phase with each other and 180.degree. out of phase with the first and third coils. Taking into account the three modes of operation, substantial magnetic fields are generated in each of three mutually orthogonal directions so that a substantial deactivation field is provided along the length of the marker to be deactivated, regardless of the direction of orientation of the marker relative to the coil array. Two-coil and quadrature-…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.