Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1996-05-06
1998-03-10
Hofsass, Jeffery
Communications: electrical
Condition responsive indicating system
Specific condition
340572, 324239, 324243, G08B 1324
Patent
active
057266280
ABSTRACT:
A metal detector system is described for detecting metal objects in a monitoring zone, where the metal detector system comprises: (a) a transmitter coil for generating a magnetic filed in the zone to be monitored, the coil being disposed on a first side of the zone; (b) a first sensing coil disposed on a second side of the zone opposed to the first side, the first sensing coil generating a first sensing signal in response to perturbations in the magnetic field caused by the presence of a metallic object in the zone; (c) a second sensing coil disposed on the second side of the zone, the second sensing coil being spaced apart from the first sensing coil, the second sensing coil generating a second sensing signal in response to perturbations in the magnetic field caused by the presence of a metallic object in the zone; and (d) a sensing circuit for comparing the amplitudes of the first and second sensing signals to generate a difference signal and for generating a first trigger signal for a zero down-crossing of the difference signal and for generating a second trigger signal for a zero uncrossing of the difference signal, wherein the trigger signals indicate direction of travel of a metal object in the zone in relation to the first and second sensing coils.
REFERENCES:
patent: 3697972 (1972-10-01), Brown
patent: 3707672 (1972-12-01), Miller et al.
patent: 3758849 (1973-09-01), Susman et al.
patent: 3763424 (1973-10-01), Bennett, Jr. et al.
patent: 3950696 (1976-04-01), Miller et al.
patent: 4675658 (1987-06-01), Anderson et al.
patent: 4677384 (1987-06-01), Payne
patent: 4779048 (1988-10-01), Aichele
patent: 4821023 (1989-04-01), Parks
patent: 5121105 (1992-06-01), Aittoniemi
patent: 5397986 (1995-03-01), Conway et al.
patent: 5406259 (1995-04-01), Manneschi
patent: 5521583 (1996-05-01), Frahm et al.
GD Electronics, Inc.
Hofsass Jeffery
La Anh
Park John K.
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