Coated windshield with special heating circuit for wiper arm storage area

• US 5,434,384 A
• Filed: 07/22/1991
• Issued: 07/18/1995
• Est. Priority Date: 07/22/1991
• Status: Expired due to Term

• Current Assignee: Pittsburgh Glass Works LLC (LKQ Corporation)
• Original Assignee: PPG Industries Incorporated (Nouryon BV)
• Inventors: Koontz, Harry S.
• Primary Examiner(s): Reynolds, Bruce A.
• Assistant Examiner(s): SWITZER, MICHAEL
• Application Number:
  US07/733,785
• Time in Patent Office: 1,457 Days
• Field of Search: 219/203, 219/543, 219/522, 219/547, 219/541, 52/171, 244/134 D, 296/84.1
• US Class Current: 219/203
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B60S 1/026 using electrical means
• CPC Class Codes: B60S 1/048 with a heating device for the wiper parking position
• CPC Class Codes: H05B 2203/002 Heaters using a particular layout for the resistive material or resistive elements
• CPC Class Codes: H05B 2203/031 Heaters specially adapted for heating the windscreen wiper area
• CPC Class Codes: H05B 3/84 Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields

Abstract

A windshield having an upper vision area with a coating and a lower heating area aligned with a wiper blade storage area. When the coating is electroconductive, first and second bus bars are provided to selectively connect the coating to the terminals of a power source to provide a windshield heating circuit for defogging or defrosting its vision area. One of the bus bars is also connected to a heating element along a lower area of the windshield that faces a storage area for windshield wipers. The heating element is selectively connected to a different terminal of the power source from the terminal connected to one of the bus bars to cooperate with one of the bus bars and the power source to provide a storage area heating circuit. The windshield heating circuit and the storage area heating circuit may be operated independently, either separately or simultaneously, from a common electric power source.

Claims

1. A windshield having a glass sheet provided with an electroconductive coating over a major surface of said sheet, a first bus bar extending along a lower edge of said sheet and electrically interconnected along its length to said coating, a second bus bar spaced from and generally parallel to said first bus bar and electrically interconnected along its length to said coating wherein said second bus bar divides said coating into a first portion over an upper major vision area and a second portion over a lower heating area facing a wiper blade storage area, said second portion being bounded by said first and second bus bars, and means to connect only said bus bars to a power source to selectively heat said wiper blade storage area.

2. The windshield as in claim 1, wherein said coating over said major vision area is at least 70% transparent to visible light.

3. The windshield as in claim 1 wherein said second coating portion has a surface watt density between approximately 1 to 2 watts per square inch.

4. A windshield having a glass sheet provided with an electroconductive coating over a major surface of said sheet, said coating having a first portion over a major vision area of said sheet and a second portion over a wiper blade storage area, a peripherally extending uncoated frame area defining said vision and storage areas therein, an upper bus bar in electrical contact along its length with an upper edge of said first coating portion and having an extension which extends around said coating along said frame area in insulated relation to said coating, said upper bus bar extension constructed and arranged for connection of said upper bus bar to a first terminal of a power source, a lower bus bar in electrical contact along its length with a lower edge of said first coating portion and having an extension insulated from said upper bus bar extension, said lower bus bar extension being constructed and arranged for connection to a second terminal of said power source, whereby said upper and lower bus bars and said first coating portion cooperate with said power source to form a first heating circuit, and wherein said second coating portion is positioned along a lower portion of said sheet and spaced from said lower bus bar and lower bus bar extension, with a first end of said second coating portion electrically interconnected to said lower bus bar or lower bus bar extension and an opposing end of said second coating portion electrically interconnected to a terminal of said power source by a connector, whereby said lower bus bar or lower bus bar extension, said second coating portion and said connector cooperate with said power source to form a second heating circuit, and further including means to selectively direct power from said power source to said first and second heating circuits to selectively energize said first and second coating portions and heat said vision area and storage area, respectively.

5. The windshield as in claim 4 wherein said selective power directing means includes first switching means to control energizing of said first heating circuit and second switching means to control energizing of said second heating circuit.

6. The windshield as in claim 4 wherein the composition of said first and second coating portions of said electroconductive coating are substantially identical.

7. A windshield having a glass sheet provided with an electroconductive coating over a major surface of said sheet, said coating having a first portion over a major vision area of said sheet and a second portion over a wiper blade storage area, a peripherally extending uncoated frame area defining said vision and storage areas therein, an upper bus bar in electrical contact along its length with an upper edge portion of said first coating portion and having an extension which extends around said coating along said frame area in insulated relation to said coating, said upper bus bar extension being constructed and arranged for connection of said upper bus bar to a first terminal of a power source, a lower bus bar extending across and dividing said coating into said first and second portions, said lower bus bar being in electrical contact along its length with a lower edge of said first coating portion and an upper edge of said second coating portion and having an extension insulated from said upper bus bar extension, said lower bus bar extension being constructed and arranged for connection to a second terminal of said power source, whereby said upper and lower bus bars and said first coating portion cooperate with said power source to form a first heating circuit a bottom bus bar spaced from said lower bus bar and electrically interconnected along its length to said second coating portion wherein said coating extends continuously from said upper bus bar across said lower bus bar to said bottom bus bar, a connector being constructed and arranged to electrically interconnect said bottom bus bar to a terminal of said power source, whereby said lower bus bar, said second coating portion and said bottom bus bar cooperate with said power source to form a second heating circuit, and means to selectively direct power from said power source to said first and second heating circuits to selectively energize said first and second coating portions of said vision area and storage area, respectively.

8. The windshield as in claim 7 wherein said selective power directing means includes first switching means to control energizing of said first heating circuit and second switching means to control energizing of said second heating circuit.

9. The windshield as in claim 7 wherein said bottom bus bar includes two bottom bus bars extending on opposite sides of said lower bus bar extension.

10. The windshield as in claim 7 wherein the composition of said first and second coating portions of said electroconductive coating are substantially identical.

11. A windshield having a glass sheet provided with an electroconductive coating over a first major surface of said sheet, said coating having a first portion forming a first heating element over a major vision area of said sheet and a second portion forming a second heating element over a wiper blade storage area a peripherally extending uncoated frame area defining said vision and storage areas therein, an upper bus bar in electrical contact along its length with an upper edge of said first coating portion and having an extension which extends around said coating along said frame area in insulated relation to said coating, said upper bus bar extension being constructed and arranged for connection of said upper bus bar to a first terminal of a power source, a lower bus bar in electrical contact along its length with a lower edge of said first coating portion and having an extension insulated from said upper bus bar extension, said lower bus bar extension being constructed and arranged for connection to a second terminal of said power source, whereby said upper and lower bus bars and said first coating portion cooperate with said power source to form a first heating circuit for said first heating element, and wherein said second coating portion is positioned along a lower portion of said sheet and spaced from said lower bus bar with a first end of said second coating portion electrically interconnected to said lower bus bar and an opposing end portion of said second coating portion electrically interconnected to said lower bus bar extension, a connector constructed and arranged to electrically interconnect said second coating portion to a terminal of said power source at a location intermediate said ends of said second coating portion, whereby said lower bus bar, said lower bus bar extension, said second coating portion and said connector cooperate with said power source to form a second heating circuit for said second heating element, and means to selectively direct power from said power source to said first and second heating circuits to selectively energize said first and second coating portions and heat said vision area and storage area, respectively.

12. The windshield as in claim 11, further including means to electrically interconnect said second coating portion at selected sites along its length to said lower bus bar and said connector includes a plurality of connectors, each electrically interconnected with said second coating portion between said selected connection sites of said second coating portion to form a plurality of heating element portions.

13. The windshield as in claim 11, further including a third heating element including a third coating portion extending along a lower portion of said sheet on an opposite side of said lower bus bar extension, said third coating portion being spaced from said lower bus bar and lower bus bar extension and having a first end electrically interconnected to said lower bus bar and an opposing end electrically interconnected to a terminal of said power source by an addition connector, whereby said lower bus bar, said third coating portion and said additional connector cooperate with said power source to form a third heating circuit, and further wherein said power directing means includes means to selectively energize said third heating circuit.

14. The windshield as in claim 11 wherein the composition of said first and second coating portions of said electroconductive coating are substantially identical.

15. The windshield as in claim 11 wherein said selective power directing means includes first switching means to control energizing of said first heating circuit and a second switching means to control energizing of said second heating circuit.

16. The windshield as in claim 11 wherein said connecting wire is connected at the midpoint of said second coating portion.