MOTOR VEHICLE ELECTRICALLY HEATED WINDSHIELD AND BACKLIGHT SYSTEM

• US 3,752,348 A
• Filed: 08/30/1971
• Issued: 08/14/1973
• Est. Priority Date: 08/30/1971
• Status: Expired due to Term

• Current Assignee: Charles D. Simmons, Donald J. Ray, Richard T. Dickason
• Original Assignee: Charles D. Simmons, Donald J. Ray, Richard T. Dickason
• Inventors: Dickason, Richard T., Ray, Donald J., Simmons, Charles D.
• Primary Examiner(s): Bartis, A.
• Application Number:
  US05/176,083
• Time in Patent Office: 715 Days
• Field of Search: 219/202,203,279,522,543,547,476-480 338/308,309 52/171
• US Class Current: 219/203
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10192 patterned in the form of columns or grids
• CPC Class Codes: B60S 1/026 using electrical means

Abstract

A system is described for electrically heating a motor vehicle windshield and backlight. The system includes a windshield having at least two conductive surfaces and a backlight having at least one conductive surface. Each of the conductive surfaces is provided with a pair of bus bars spaced from one another to permit flow of electrical charge therebetween via the conductive surfaces. This generates heat in the windshield and backlight for defogging and defrosting purposes. The system includes a three phase alternator having the conductive surfaces of the windshield and backlight connected thereto to provide substantially balanced loading of the alternator phases. The alternator may have a field winding supplied by a dc source of electrical energy located in the motor vehicle. A switch connected in series with the field winding may be provided to energize the system. Over-temperature protection for the alternator may be achieved by the provision of a thermostat also connected in series with the alternator field winding.

Claims

1. An electrically heated windshield and backlight system for a motor vehicle, which comprises:

a windshield having first and second transparent conductive surfaces, said first and second conductive surfaces being electrically insulated from one another by an imaginary plane passing vertically through said windshield to divide it into symmetrical halves, said windshield including a first pair of bus bars in electrical contact with said first conductive surface, said first pair of bus bars being spaced from one another to permit electrical charge to flow from one to the other via said first conductive surface, and said windshield further including a second pair of bus bars in electrical contact with said second conductive surface, said second pair of bus bars being spaced from one another to permit electrical charge to flow from one to the other via said second conductive surface;

a backlight including a third conductive surface and a third pair of bus bars in electrical contact with said third conductive surface, said third pair of bus bars being spaced from one another to permit electrical charge to flow from one to the other via said third conductive surface; and

a three-phase alternator having first, second, and third phase winding line terminals, said first conductive surface being electrically connected between said first and third line terminals, said second conductive surface being electrically connected between said first and second line terminals, said third conductive surface being electrically connected between said second and third line terminals, said alternator being driven by the engine of said motor vehicle and generating voltage in excess of 80 volts between its line terminals;

thereby to permit said backlight and windshield conductive surfaces to be heated while permitting substantially balanced loading of said alternator if the resistances of each of said conductive surfaces are made substantially equal.