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Windshield wiper rain sensor system

  • US 5,780,719 A
  • Filed: 01/22/1997
  • Issued: 07/14/1998
  • Est. Priority Date: 01/22/1997
  • Status: Expired due to Fees
First Claim
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1. A rain sensor system for automatically controlling windshield wiper action, the rain sensor system comprising:

  • first and second electrical conductors uniformly spaced in parallel relationship with one another and having first and second exposed conductive surfaces respectively, and each conductor having an elongated shape;

    a voltage divider circuit coupled to a DC supply voltage for imposing on the first conductor an applied voltage having a magnitude between that of the DC supply voltage and ground potential, the second conductor being coupled to ground potential; and

    an electrical insulator interposed between and coextensive with the first and second parallel, elongated conductors such that the first and second conductors and the insulator together form a thin elongated body resembling in shape a whip-type antenna for a vehicle, the insulator having an exposed insulating surface located between the first and second exposed conductive surfaces of the respective first and second conductors;

    means for mounting the conductors and insulator to project outwardly from a vehicle exterior surface in an unobstructed location into oncoming airflow such that the airflow parts and flows around the conductors and insulator and airborne raindrops temporarily adhere to the exposed insulating surface to electrically couple the first and second conductive surfaces and lower the electrical resistance between the conductors, whereby the magnitude of the applied voltage changes in relation to the intensity of rainfall or raindrops adhering to the first and second conductors; and

    wiper control means coupled to the first conductor for generating a wiper control signal in accordance with the magnitude of the applied voltage and intensity of the rainfall.

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