Window cleaning fluid heating system having timer-controlled heater and differential input circuit

  • US 5,354,965 A
  • Filed: 03/16/1992
  • Issued: 10/11/1994
  • Est. Priority Date: 08/21/1990
  • Status: Expired due to Fees
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First Claim
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1. A windshield cleaning fluid heating system comprising:

  • a metal vessel having an internal chamber for holding a volume of windshield cleaning fluid, the metal vessel being connected between a windshield cleaning fluid reservoir and at least one nozzle means for spraying a stream of windshield cleaning fluid on a windshield, whereby windshield cleaning fluid can be pumped from said reservoir, through said internal chamber and to said nozzle means;

    a plurality of metal pins extending into said internal chamber and in thermal contact with a heater wall of said metal vessel, each of said plurality of metal pins having a tapered cylindrical shape;

    at least one thermistor positioned on said heater wall outside of said internal chamber, for providing heat to said heater wall and to the plurality of metal pins; and

    a control means electrically connected to the thermistor for controlling the heat provided by the thermistor, the control means comprising a timing means for setting a period of time during which the thermistor will heat said volume of cleaning fluid, an engine sensor means for sensing whether an internal combustion engine is running and for preventing the thermistor from being activated if said internal combustion engine is not running and a differential input circuit means for ensuring that a usable signal is delivered to said timing means independent of the manner in which said control means is connected to a pair of electrical terminals of a pump for pumping windshield cleaning fluid from said reservoir to said nozzle means.

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