Gebogene Glasscheiben mit UEberzuegen und Verfahren zu ihrer Herstellung sowie aus derartigen Glasscheiben bestehende Gegenstaende

摘要

In a method of providing a glass sheet with a non-uniform metal oxide film by spraying on to the sheet heated to a temperature above 400 DEG F. and below the softening temperature of the sheet a film forming composition capable of producing a metal oxide film thereon, the sheet is oriented in a fixed plane, the spray is applied from a point of origin spaced from the plane of the sheet to a portion of the sheet, the spray is maintained about a central p axis having a fixed oblique angular relationship to the plane of the sheet and relative motion is provided between the heated oriented sheet and the spray transverse to a line which is the projection of the central axis of the spray on the sheet so that a film of non-uniform thickness is formed on the sheet, the thickness varying from a minimum along the line of intersection from an edge of said spray traversing the shortest possible straight line distance from the origin of the spray to the coated portion and increasing to a maximum along an edge of the sheet included in the portion directly exposed to the spray. A preferred filming composition is one which produces a film containing cobalt oxide as a major ingredient with optionally nickel oxide, iron oxide, and tin oxide as minor ingredients. As shown, apparatus for carrying out the process comprises a pair of spray guns 30, Fig. 2, carried on vertical posts 32. The spray guns are urged upwardly by springs 34 against a curved cam rail 46 forming part of the carriage 40 conveying the sheet past the spray guns. Preferably one of the spray guns is directed upwards at an angle of about 30 degrees to the plane of the glass sheet and the other spray gun at an angle less than 30 degrees. Each gun carries a shield 38 to delineate one boundary of the spray. The shape of the cam rail 46 is such that the boundary produced when the sheet is subsequently bent will be approximately a straight line. In an alternative form of apparatus, Fig. 5, the glass sheet 10 is horizontal and the spray is applied thereto at an acute angle. A baffle sheet 66 is used to prevent drippings from the spray guns contacting the sheet. Specifications 704,793 and 822,295 also are referred to.