Patents by Inventor Henry F. Pfister

Henry F. Pfister has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Coil assembly for substantially isotropic flux linkage in a given plane
    Patent number: 4628324
    Abstract: A coil assembly that is essentially isotropic in a plane normal to the plane of the coil includes two flat coils stacked one next to the other. One coil is connected in series with a resistor in a closed loop and has a strip of high permeability material woven through it. The other coil is tuned by a parallel capacitor across its coil terminals, such terminals being connected to electronic circuitry. The coil is separated from the printed circuit board that contains the electronic circuitry by a sheet of high permeability material. The assembly is self-contained and powered by a flat battery on which the circuit board is placed. Another embodiment is disclosed that contains only one coil, the terminals of which are connected to a suitable electronic circuit, not shown. Strips of high permeability material are disposed on both sides of the coil and an assembly is produced with a printed circuit board and a flat battery.
    Type: Grant
    Filed: October 1, 1985
    Date of Patent: December 9, 1986
    Assignee: Sensormatic Electronics Corporation
    Inventors: Thomas A. O. Gross, Raymond L. Barrett, Jr., Henry F. Pfister
  • Coil assembly for substantially isotropic flux linkage in a given plane
    Patent number: 4549186
    Abstract: A coil assembly that is essentially isotropic in a plane normal to the plane of the coil includes two flat coils stacked one next to the other. One coil is connected in series with a resistor in a closed loop and has a strip of high permeability material woven through it. The other coil is tuned by a parallel capacitor across its coil terminals, such terminals being connected to electronic circuity. The coil is separated from the printed circuit board that contains the electronic circuitry by a sheet of high permeability material. The assembly is self-contained and powered by a flat battery on which the circuit board is placed. Another embodiment is disclosed that contains only one coil, the terminals of which are connected to a suitable electronic circuit, not shown. Strips of high permeability material are disposed on both sides of the coil and an assembly is produced with a printed circuit board and a flat battery.
    Type: Grant
    Filed: April 14, 1982
    Date of Patent: October 22, 1985
    Assignee: Sensormatic Electronics Corporation
    Inventors: Thomas A. O. Gross, Raymond L. Barrett, Jr., Henry F. Pfister
  • Signal direction determining system and directional loop antenna array therefor
    Patent number: 4489313
    Abstract: A directional loop antenna array is provided by two flat parallel spaced apart open loops with a shorted turn disposed between the open loops equidistant therefrom. The signals from the open loops are vectorially added and subtracted in a sum and difference circuit and the phase angle between the sum and difference signals is ascertained in a phase detector circuit that feeds an indicator. The so determined phase angle is either greater or less than 90.degree. depending upon the relative magnitudes of the loop signals.
    Type: Grant
    Filed: September 1, 1982
    Date of Patent: December 18, 1984
    Assignee: Sensormatic Electronics Corporation
    Inventor: Henry F. Pfister