Ppg Industries, Inc.

Samuel L Seymour

Robert G Frank

George R Claassen

Michael T Fecik

John J Ewing

Edward A Thimons

Joseph C Pavlik

Robert E Dunn

A heat softened glass sheet is lifted within a heating furnace by a vacuum pickup and moved to a shaping station adjacent the furnace where it is deposited on an aligning frame. The location of the sheet is identified and the frame is moved to position the supported glass sheet at a predetermined location between a pair of vertically aligned upper and lower full surface press faces. A shuttle frame which moves the vacuum pickup has integral vacuum passageways so that vacuum for the pickup can be drawn through the shuttle frame.

Method and apparatus for shaping glass sheets

A horizontal press bending arrangement wherein heat softened glass sheets are engaged by a shuttling vacuum pickup. The pickup and sheet are transferred out of the furnace and into a shaping station wherein the glass sheet is deposited and repositioned between a pair of vertically aligned full surface press faces.

Horizontal press bending of heat softened glass sheets

The present invention relates to a ring-like member for use in a glass sheet bending and tempering process most adapted to a process wherein a glass sheet is released from engagement against a vacuum mold of a shape having sharply bent regions about longitudinally spaced, transversely extending lines of relatively sharp bending onto said ring-like member. The vacuum mold has a distance between the sharply bent regions at operating conditions that either equals or is slightly less than the distance desired in the bent glass. In a preferred embodiment, the ring-like member is split into two shaping rails, which are separable to adjusted positions wherein the sharply bent regions are spaced to conform to the distance desired therebetween in the bent glass sheet.

Split ring-like support member of adjustable length for shaping glass

Apparatus capable of tempering bent glass sheets of different sizes and shapes including sharp bends about axes oblique to the length and width of the glass sheets is made possible by supporting end nozzle boxes of tempering apparatus in such a manner that they can be moved relative to center nozzle boxes and also permitting limited pivotal adjustment of the end nozzle boxes about both essentially horizontal and essentially vertical axes to permit the end nozzle boxes to move into positions conforming to the shape of corresponding end portions bent to different orientations relative to the length and/or width of the central portion of the bent glass sheets having different glass sheet patterns, including flat patterns.

Apparatus for tempering glass sheets of different sizes and shapes

A flat glass sheet of a given outline configuration is supported in a shaping station by a combination of a gas hearth bed portion and readily replaceable flat plate means comprising spaced plates having spaced edges of conforming shape that define an elongated slot conforming to the outline shape of at least a portion of the periphery of the flat glass sheet. The gas support bed portion provides hot gas under pressure to float the flat glass, and the flat plate means is located in close proximity to an end of the gas hearth bed portion to provide a narrow space at the level of the gas hearth bed portion for escaping gas between the flat plate means and the extending glass sheet portion to limit sag of the extending glass sheet portion. The flat plate means may be covered by material that does not mar hot glass, such as boron nitride, in case the glass sheet portion sags a limited distance to slide in contact with the flat plate means before it is lifted on a shaped, ring-like member.

Support for hot glass sheets of non-rectangular outline prior to bending

This invention relates to heat treating glass sheets, and particularly relates to shaping and tempering a glass sheet comprising a step of supporting the sheet while heat softened with its upper surface against a glass sheet holder. In order to minimize surface distortion resulting from the heat-softened glass sheet replicating any surface deficiencies in the holder such as surface blemishes if the sheet is forced against a continuous surface by an upward flow of gas pressure, or those resulting from perforations through the bottom wall of the holder if the holder is of the vacuum type that holds the glass sheet thereagainst by suction, the present invention interposes a soft, fluffy, porous cover of fiber glass fabric, perferably knit fabric composed of texturized yarns between the upper surface of the glass sheet and the glass sheet holder. Other optional features of this invention comprise the use of more precise temperature control in the form of electrical resistance heaters to irradiate the upper surface of the glass sheet while a gas hearth is used to both heat and float the glass sheet, heating the upper glass sheet surface to a maximum temperature of about 10.degree. F. to 50.degree. F. less than the maximum temperature of the lower surface of the sheet so that the upper glass sheet surface that engages the soft, fluffy, porous cover is relatively hard compared to its surface hardness were the glass sheet heated to a uniform temperature throughout its thickness when the sheet is heated to an overall temperature suitable for tempering.

Minimizing surface distortion while shaping glass sheets

In tempering a glass sheet, particularly a glass sheet having at least one major dimension more than 0.5 meter, by quenching said sheet with cold tempering medium while at a tempering temperature, prior art tempering apparatus developed insufficient temper particularly in the central portion of the glass sheet, as evidenced by fragments from the central portion exceeding code requirements for maximum size on destruction testing. The present invention provides a novel construction and arrangement of the tempering medium supply system that provides relatively wide escape paths in the direction of the glass sheet thickness for blasts of tempering medium applied toward the central portion of the glass sheet compared to the escape paths provided in said direction for blasts of tempering medium applied to the portion of the glass sheet beyond the central portion. The resulting tempered glass sheets processed using the present invention have fragments that meet code requirements in the central portion as well as the portion beyond the central portion when subjected to destruction testing.

Glass sheet tempering apparatus with nozzle arrangement providing fluid

When glass sheets are shaped by drop forming a glass sheet released from vacuum engagement against the bottom perforated plate of a vacuum platen to drop onto a shaping mold of ring-like construction, the intermediate portion of the glass sheet can develop excessive downward sag. The present invention discloses different techniques to develop an upward bow in the intermediate portion of the glass sheet sufficient to compensate approximately for the undesired excessive downward sag.

Shaping glass sheets by drop forming with improved sag control

Glass sheets arriving at a bending station where their under surfaces are exposed to a hot gas support bed are delivered with minimum misalignment and misorientation by engaging each sheet simultaneously across its entire width with at least two rotating conveyor rolls. The latter are spaced from one another longitudinally of a path of glass sheet travel a distance sufficient to optimize flow of hot gas against the engaged glass sheet surface. This invention enables the leading edge of glass sheets of either rectangular or non-rectangular outline to nest within aligning means located in a fixed but adjustable position at the bending station. Provision is made to handle two or more sheets arriving at the bending station in side-by-side relation.

Delivering and aligning glass sheets in a bending station

Heat-softened glass sheets are shaped by being lifted by vacuum drawn through a platen and then dropped onto a shaping mold. The dropping of the glass sheets is assisted by rapidly replacing the vacuum in the platen with super-atmospheric pressure.

Shaping glass sheets by drop forming with pressure assist

Heat-softened glass sheets are held by a flat vacuum platen and dropped onto a shaping mold to impart the desired curvature to the glass sheet.

Method and apparatus for shaping glass sheets by drop forming

Heat softened glass sheets are held by a flat vacuum platen, portions of the glass sheet are pre-shaped by auxiliary shaping means while the glass sheet is being held, and then the glass sheet is dropped onto a shaping mold to impart the complete desired curvature to the glass sheet.

Drop forming glass sheets with auxiliary shaping means

In a drop forming process for shaping glass sheets, wherein a glass sheet is dropped from a flat vacuum platen onto a shaping mold, the final curvature of the glass is controlled by releasing a portion of the glass sheet from the platen prior to releasing the remainder of the glass sheet.

Shaping glass sheets by drop forming with differential vacuum release

Spacer elements affixed to the face of a flat vacuum platen induce a temporary reverse bow in a heat softened glass sheet held on the platen. The bowing is in the opposite direction from that of the final curvature, so that when the glass sheet is subsequently dropped onto a shaping mold the resulting sag in at least one direction is reduced.

Shaping glass sheets by drop forming with sag control means

In tempering glass sheets vertically hung from tongs, the uniformity with which tempering medium is applied toward the glass sheets during quenching is improved by providing the quenching apparatus with means to provide finer control of the flow rate of tempering medium against the opposite major surfaces of the glass sheets than one gets from valving branch conduits in order to prevent side-to-side swaying of the glass sheets during quenching, particularly when the sheets are curved. Such means to provide fine control is also useful in quenching glass sheets supported in other than vertical orientations during quenching.

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Oakmont, PA, United States of America

Samuel L Seymour