Patents by Inventor Åke Pettersson

Åke Pettersson 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).

  • Deteriorated filament detection
    Patent number: 6556017
    Abstract: A Method and an arrangement providing detection of deteriorated lamp filaments (3) in a lamp circuit (11) fed by constant current, in particular for a lamp supervision system for airfield lights. A change in a constant current fed through a lamp circuit (11) is initiated, whereby the lamp filament resistance is determined once in conjunction with the change in current and once a time period later. A difference between the resistance determinations constitutes the deterioration of a lamp filament (3) in comparison with a threshold value. Hence, no record of previous resistance determinations have to be stored, and lamps (4) can be replaced when the difference matches the threshold value.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: April 29, 2003
    Assignee: Safegate International AB
    Inventor: Åke Pettersson