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US 4,902,875 AGranted
Power discontinuity sensor for a dual feed heatable windshield
AssigneePPG Industries, Inc.
InventorHarold S. Koontz
Life of this patent
Estimating the term…
Abstract
A power discontinuity sensor for a heatable windshield with bus bars having a double lead configuration. Sensor lines extend around the perimeter of the windshield in close proximity to adjacent bus bars or leads. The sensor lines are provided with current from an upper bus bar through a connecting bridge along the upper bus bar. Voltage in the sensor lines is monitored and current to the bus bars is interrupted in response to predetermined variations in the measured voltage.
Claims20
An electrically heatable transparency comprising:
- a non-electrically conductive substrate;
- a first bus bar on a surface of said substrate;
- a second bus bar on said surface of said substrate spaced from said first bus bar;
- an electroconductive heating member on said substrate interconnecting said first and second bus bars;
- first and second electroconductive leads electrically insulated from said electroconductive member and said second bus bar and each having a first end connected to said first bus bar and an opposing second end;
- a sensor filament electrically insulated from said bus bars, leads, and electroconductive member to detect a power discontinuity in selected portions of said first bus bar and leads;
- and
- means to electrically interconnect an end of said filament with said first bus bar or one of said leads at a location such that said selected portions are positioned between said interconnecting means and said second end of said lead.
5 more elements
An electrically heatable transparency comprising:
- a non-electrically conductive substrate;
- a first bus bar on a surface of said substrate;
- a second bus bar on said surface of said substrate spaced from said first bus bar;
- an electroconductive heating member on said substrate interconnecting said first and second bus bars;
- first and second electroconductive leads electrically insulated from said electroconductive member and said second bus bar and each of said leads having a first end connected to said first bus bar;
- at least one sensor filament electrically insulated from said bus bars, leads, and electroconductive member;
- and
- means to electrically interconnect an end of said filament with said first bus bar or said first end of one of said leads.
5 more elements
Dependencies are inferred from the claim text.