Flachglas Aktiengesellschaft

Pilkington Automotive Deutschland Gmbh

Pilkington North America, Inc.

Flachglas Automotive Gmbh

Dieter Funk

Joachim Pilz

Walter Brans

Dieter Bruns

Rolf Wenning

Peter Michels

Robert J Boisselle

Andreas Gorges

The glass sheets () of an asymmetric glass-sheet pair, which is intended for the production of laminated glass, are preheated in a preheating furnace () and then undergo a press-bending process in a press-bending station (). By means of a temperature measuring point () arranged at the exit of the press-bending station, it is ensured that the glass sheets exhibit a uniform bending behavior, in order to guarantee identical restoring forces during cooling. The temperature measuring point () is connected to a control device (), which causes an intermediate cooling of the glass sheet heating more rapidly by means of an intermediate cooling installation () in the pre-heating furnace and/or lengthens its dwell time in the press-bending station () by means of a timing control element ().

Process and plant for the treatment of the glass sheets of an asymmetric glass-sheet pair

The gas cushion serves to support a preheated glass sheet and is produced by a chamber, which is connected to a source () of compressed gas. The upper wall () of the chamber is adapted to the shape of the glass sheet and has a plurality of apertures for the passage of gas in the form of nozzles (), which comprise an entry bore () and, following thereupon, a progressively widening exit hole () with a nozzle exit area (). The upper wall () of the chamber has a greater degree of perforation (sum of the nozzle exit areas () in relation to the total area of the respective zone) in its edge zone () than in its central zone (). The nozzles ensure that no jet marks can arise. The gas of the gas cushion can also flow out undisturbed at the side, so that no cooling edges are present and the occurrence of cooling shadows is accordingly avoided.

Device for producing a gas cushion

A press bending station includes an annular mold () and a full-face mold (). Holes (), selectively connected to a negative pressure source, are placed in portions of the full-face mold () that are determined by the configuration of the annular mold when the annular mold comes into contact with a heated glass sheet () during the press bending process. The sheet () is drawn by negative pressure through the holes () towards the full-face mold () and thus acquires its shape. Positive pressure may be selectively applied to the holes () to release the sheet (). According to the invention, at least some of the holes () are arranged in at least one groove () formed in the mold face of the full-face mold. The grooves () according to the invention accelerate considerably the removal by negative pressure of the air between the molding face of the full-face mold () and the glass sheet () to be bent and thus improve the press bending process.

Press bending station for the bending of glass sheets

Process for bending the outer glass pane and the inner glass pane of laminated safety glass panes bend with predefined curvature geometry. The press-bending system incorporates a bending station, a discharge station, as well as between bending station and discharge station, a conveyor shuttle. The glass panes to be bent, heated to bending temperature, are introduced singly into the bending station with the aid of a transfer line and are bent in it, taking account of the predefined curvature geometry of the laminated safety glass panes. The outer glass pane and the inner glass pane are subjected to optimizing bending at a temperature, which is in the lower bending temperature range, in the discharge station assigned to them. To carry out optimizing bending, the glass panes are lifted off the conveyor shuttle with the aid of a take-off device, which take-off device possesses an optimizing contour at least in the edge area. The optimizing bending is carried out by placing the glass panes on the optimizing contour. Also a press-bending system to carry out the process is indicated.

Glass bending process and apparatus

Press-bending station for bending sheets of glass during the course of automated production of identical motor vehicle windows within specified batch sizes, where the glass sheets to be bent are heated in a continuous furnace to a specified bending temperature and directly after leaving the continuous furnace are fed in horizontal position with the aid of a horizontal conveyor into the press-bending station. It incorporates a male press mold and a female press mold. The male press mold is a cast full mold and consists of an aluminum alloy. The male press mold possesses heating passages for fluid heating with the aid of a liquid heat transfer medium and can be heated with sufficiently homogeneous temperature distribution to a thermal expansion temperature which is below the bending temperature. The temperature of the male press mold can be controlled and/or regulated by means of the liquid heat transfer medium. The thermal expansion temperature of the male press mold is controlled and/or regulated such that the specific thermal expansion of the male press mold and the thermal expansion of the glass sheet to be bent, placed centrally on the female press mold at bending temperature, practically correspond.

Glass bending press application

Process for operation of a press-bending station for bending glass sheets during the course of automated production of motor vehicle windows, during which manufacture the glass sheets to be bent are fed into a cyclically operating press-bending station, and after the bending operation are fed out of the press-bending station with the aid of a means of conveyance in the form of a shuttle ring into a cooling and/or toughening station. The press-bending station incorporates in its press an upper male press mold with vacuum-locating device for the bent glass sheet, a lower female press mold and the shuttle ring. The press incorporates a press upper beam which is movable up and down, to which a male press mold is attached. The bent glass sheet retained under the male press mold with the aid of the vacuum-locating device is fed to the shuttle ring by a downward movement. The downward motion is controlled or regulated according to a velocity curve which incorporates for commencement of downward motion an acceleration section, a maximum velocity curve section and a subsequent deceleration section for soft deposition of the bent glass sheet on the shuttle ring. The velocity curve is such that the first derivative of the velocity curve is free from singularities with respect to time. The reduced pressure of the vacuum-locating device is matched to the mass of the bent sheet. Deceleration of the downward motion of the press upper beam is matched to the reduced pressure of the vacuum-locating device.

Process for operating a glass-bending press

A transfer device for bent glass sheets during the course of automated production of motor vehicle glass windows on a production line with continuous furnace, bending press, toughening station and device for onward conveyance of the toughened glass sheets. The transfer device operates between the bending press and the toughening station. The transfer device is a shuttle transfer device whose shuttle is guided on shuttle guide rails. The shuttle guide rails are supported statically on the one hand on the press frame of the bending press and on the other hand on the station frame of the toughening station as beams on two supports or as continuous beams. The shuttle incorporates a shuttle frame as well as a shuttle ring mounted therein and the shuttle frame is guided on the shuttle guide rails by means of a shuttle frame mounting which movable on the shuttle guide rails. The shuttle ring is adjustable in relation to the shuttle frame mounting and thus in relation to the male bending mold. The shuttle ring incorporates on its edges positioning devices for the glass sheets received. At least the areas of the shuttle guide rails which project into the press frame of the bending press are removable for the purpose of carrying out maintenance and/or repair work on the bending press.

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Witten, Germany

Dieter Funk