420 F.2d 1070; 164 USPQ 387

IN RE ALBERT BEZOMBES, IVAN PEYCHES AND PIERRE TISSIER (No. 8226, No. 8244)

PATENTS

1. PLEADING AND PRACTICE IN PATENT OFFICE-REJECTIONS

Board's dismissal of claim limitation as "an obvious matter of choice" is not convincing in absence of some reason why a person skilled in the art would find it obvious.

United States Court of Customs and Patent Appeals, February 5, 1970 APPEAL from Patent Office, Serial Nos. 261,034 and 261,098

[Modified and Remanded]

John L. Seymour, Bauer and Seymour, attorneys of record, for appellants. Joseph Schimmel for the Commissioner of Patents. Fred W. Sherling, R. V. Lupo, of counsel.

[Oral argument December 3, 1969 by Mr. Seymour and Mr. Lupo]

Before RICH, ALMOND, BALDWIN, LANE, Associate Judges, and RAO, Judge, sitting by designation.

RICH, Judge, delivered the opinion of the court:

These two appeals are from decisions of the Patent Office Board of Appeals affirming the rejections of claims in appellants' applications serial Nos. 261,034 (Appeal No. 8226) and 261,098 (Appeal No. 8244). The applications, both filed on February 26, 1963, are entitled, respectively, "Process For The Shaping And Supporting Of Glass" and "Apparatus For The Support And Transportation Of Glass." Although only method claims are involved in Appeal No. 8226 and only apparatus claims in Appeal No. 8244, the disclosures in the two applications are apparently identical and the two appeals were argued as one and are dealt with in this single opinion.

The inventions relate to the manufacture of "flat glass," which term is said to include all sheet glass products, whether flat or curved. Applicants state that it was known to deposit glass, either in the molten state or already formed into a sheet but in the plastic state, over a support in the form of a bath of liquid having a greater density than the glass, molten metal for example, whereby the glass was maintained at the surface of the bath by hydrostatic forces. That process, which is known as the "flotation process," is stated to have certain disadvantages, including the requirement for greater quantities of liquid metal to fill the bath-containing tanks. Among the stated objects of appellants' invention are:

to support flat glass in the plastic state on capillary films of molten metal, on flowing sheets of molten metal, on thin, immobile sheets of molten metal, and on a plurality of bodies of molten metal of no great thickness.

Illustrative of the specific disclosure of the applications are Figs. 1, 2 and 3 thereof.

Fig. 1 shows a sheet of glass 1 supported above the flat surface of a floor 3 by what is described as a "capillary" layer of molten metal 2. The entire floor 3 may be of a material which is not wetted by the molten metal, as carbon, preferably in the form of graphite. If desired, a central section 3' of the floor may be made of a material which is wetted by the molten metal, only the outer portions 3" being made of a material which is not wetted by the metal. It is stated that in either case the capillary sheet of molten metal assumes a worm having rounded edges 4 and supports the glass sheet out of contact with the floor.

Fig. 2 differs from fig. 1 in that the floor 3 is provided with a central trough 5 which receives a thin sheet of metal 2, present in sufficient quantity to project above the level of the floor and form "capillary curves 7." The trough is of material not wetted by the metal.

In Fig. 3, a refractory block 15 has, on its upper surface, a shallow central trough providing a floor 3 on which is disposed a film or layer 2 of molten metal such as tin for supporting a glass sheet 1. The trough has raised edges which contain the molten metal on three sides and a weir 8 on the downstream side. (Glass flow is from left to right.) The weir stabilizes the thickness of the film or layer of molten metal, such metal as flows over it passing through conduit 12, pump 13, and conduit 12' to the upstream side of the trough. A sheet of glass 1 coming from roller on the left (not shown) is laid on the molten metal and progresses through a temperature-reducing lehr from which it is drawn off onto rollers 10. The temperature of the floor is controlled at different parts of its length by "thermal pipes" 16. By maintaining an even flow of molten metal over the weir, the under surface of the glass is kept out of contact with solid objects until it has been cooled to a viscosity at which it is not marred by contact with ordinary handling means such as metal rollers.

In addition to disclosing molten metal in the form of a continuous sheet, as shown in Figs 1 and 3, the applications reveal a number of modifications. Thus, a series of pits or grooves spaced over the surface of the floor may be overfilled with molten metal in sufficient amount to extend slightly above the level of the floor to sustain the weight of the glass sheet. It is stated that such construction provides "what is in effect a plurality of liquid bearings which support the sheet out of contact with the floor.***." Another embodiment provides spaced shallow "trays" or cavities in the floor along the path for the glass sheet, which trays are overfilled with molten metal to form supports for the glass sheet.

Additionally, it is disclosed that "gases such as hydrogen" or "argon and nitrogen" may be introduced beneath the glass sheet to prevent oxidation of the molten metal and protect the surface of the glass. Reference is also made to "introduction of inert, antioxidant or ion inhibiting gases."

In comparing their inventions with the prior art, appellants state that, in systems using deep flotation baths, the glass sheet must be lifted from the horizontal plane to a higher level to avoid contact with the borders of the tank as it leaves the bath, requiring sharp chilling of the sheet at that point to prevent the change in direction from introducing surface deformations. They further state:

That disadvantage of the prior art is overcome in the present invention by the use of the surface tension to sustain the glass sheet on a solid floor. Substantially speaking, it is the force of surface tension which support[s] the glass in some phases of this invention. In the present invention, the glass may be drawn horizontally from the surface of the liquid support, thus avoiding the internal and surface displacements which occur when the glass is bent to raise it to the level of a higher conveyor

Appeal No. 8226

In this appeal, claims 1-3, 5-14, 16, 22, and 27 stand rejected on prior art. These claims also were rejected, along with claims 23 and 26, the only other claims in the application, for double patenting.

Claims 1, 2, 11, 12, 16, and 27 are representative:

1. In a method of making flat glass wherein a sheet of flat glass is formed from molten glass and is deposited on and moved over the receiving floor of a solid bed, the step which comprises interposing between the sheet and the floor a support of molten metal of thickness measured above the floor not substantially greater than that of the glass sheet, not larger than the glass sheet, and so disposed as to separate the sheet from the floor, cooling the sheet progressively as it advances over the floor until it can be handled without damage by other han dling means, and transferring the glass to other handling means.

2. In a method of handling flat glass wherein a sheet of flat glass is deposited on and moved over a receiving floor forming part of a solid bed, the step which comprises interposing between the sheet and the floor a support of molten metal of thickness measured above the floor not substantially greater than that of the glass sheet, and so disposed as to separate the sheet from the floor, cooling the sheet and transferring the glass to other handling means.

11. In a method of supporting a sheet of glass at high temperature on a plurality of oxidizable molten metal bearings ["the step"?] which comprises introducing a protecting gas, of the type comprising neutral and reducing gases, between the bearings.

12. The method of casting flat glass which comprises forming a sheet from molten glass, forming a sufficient quantity of molten noncapillary metal in a state of equilibrium between the forces of surface tension and the forces of gravity to receive and support the glass sheet, laying the glass sheet upon the molten metal and moving it thereover, cooling the glass sheet in contact with the molten metal, and transferring the sheet to other supporting means.

16. A method of transporting a glass sheet in a plastic state in which the glass sheet is deposited on a solid surface which comprises interposing between said solid surface and the glass sheet a liquid film acting as lubricant for facilitating the gliding of the glass sheet on said support.

27. A method of supporting a surface of an object out of contact with a floor which comprises establishing a thin support of molten metal, which does not wet the said surface and does not wet the floor, between the surface and the floor to a depth which just lifts the surface clear of the floor.

The references relied on by the board are:

Hitchcock_.

Coxe_____

British Patent___.

789, 911 May 16, 1905 2,298, 348 Oct. 13, 1942 874, 534 Aug. 10, 1961

Hitchcock discloses a method of manufacturing glass best described with reference to Fig. 2, a cross-sectional elevation of his apparatus. In the figure, plastic glass in chamber 1 flows through a slot 3 into chamber 4 in which it is hardened and annealed. In that chamber, the sheet of glass is supported on "a practically continuous" bed 5, formed of liquid metal having a melting point lower than the temperature of the glass sheet and a specific gravity greater than that of the glass, so that the sheet will float on the surface of the molten metal. The tank holding the molten metal bath 5 is divided into a series of compartments by the partitions 6 which "extend nearly to the surface of the liquid bed and have their upper edges reduced to nearly knifeedges ***." These partitions substantially prevent movement of metal from one compartment to another and the compartments can be maintained at progressively lower temperatures to gradually cool the glass. Electric resistance heaters are shown at 7.

Arranged downstream of the chamber 4 is an auxiliary chamber 13 in which the annealing of the sheet is completed. The auxiliary chamber 13 is provided with a liquid bed which "is preferably formed of mercury." The bottom or "floor" of chamber 13 is provided with with ribs or ridges, which prevent "any such movement of the liquid bed as would tend to produce uniformity of temperature at the ends of the bed."

Coxe discloses an arrangement for forming sheet metal, aluminum for example, on the top of a molten bath of a metal, such as lead, having a lower melting point and a higher specific gravity than the metal being so formed. To prevent the molten metal of the bath from attaining a higher temperature than desired, it may be drawn off at the downstream end and passed through a pipe and cooler back to the upstream end.

The British patent discloses a method of producing glass sheet wherein the sheet is supported on a bed of carbonaceous material or on rollers of such material. The supporting material or rollers may be protected from deterioration by a nonoxidizing atmosphere of a gas