Overpressure-assisted gravity bending method and suitable devices therefor

Abstract

The invention relates to a device for bending at least one glass sheet (I), comprising at least a gravity bending mold (1) with a support surface (2) suitable for at least one glass sheet (I) arranged thereon, An upper forming tool (3) arranged opposite to the support surface (2) is suitable for forming the surface ( O) an overpressure is generated, wherein the forming tool (3) has a cover plate (8) configured to open the cavity in the direction of the gravity bending mold (1) and is equipped to introduce gas into the cavity for Devices for generating overpressure and in which the cavity is divided by at least one partition wall (12) into at least two sub-chambers (5.1, 5.2), so that different pressure, and wherein the forming tool (3) is equipped with a common gas delivery pipe (6) up to which the partition wall (12) extends.

Description

technical field [0001] The invention relates to an overpressure-assisted gravity bending method for glass panes, a device suitable for this and the use of an upper forming tool for generating an overpressure in the gravity bending method. Background technique [0002] Glazing for motor vehicles often has curvature. A popular method for bending glass sheets is so-called gravity bending (also known as gravity bending or sag bending). In this case, the flat glass pane is arranged in the starting state on the support surface of the bending mold. The plate is then heated to at least its softening temperature, so that it bears against the support surface under the influence of gravity. Through the design of the support surface, the shape of the glass pane can be influenced in this way. The final bend is achieved by gravity bending. Such a method is eg known from GB 813069 A. In the case of more complex plate shapes, however, multi-stage bending methods are often used. Usuall...

AI Technical Summary

Problems solved by technology

[0003] Disadvantages of traditional gravity bending methods include high bending temperatures to effectively soften the glass sheet and long bending times until the sheet assumes its desired shape

Both lead to increased production costs

Furthermore, bending defects arise in the case of more complex multi-stage bending processes in which the glass sheet after gravity bending is transferred by the gravity bending die to another, more strongly bent, lower bending die: directly after transfer the glass The sheet is placed on the new bending mold at only three or four points, before the glass sheet is set in a new shape, where, due to higher loads at these points, undesired Bending (so called Counterbending or Crossbending)

Such tools are complex to manufacture and maintain due to the multiple independent gas delivery tubes

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