Bending of windows by gravity collapse using a multiplicity of supports, notably for providing deep concavity for such windows as motor vehicle windscreens

摘要

Bending of a window comprises: (a) a first stage of bending by gravity collapse on a first support to procure a first central collapse; (b) a second stage of bending by gravity collapse on a second support to procure a second more pronounced central collapse and until all the periphery of the window comes into contact with the second support, the window being at a temperature sufficient for the central part may continue to collapse after contact with all of the periphery; (c) a third stage following the bending of the window by gravity collapse to procure a third central collapse more pronounced than the second, the periphery always being in contact with the second support; and (d) a fourth stage stopped by cooling the collapse of the window and giving it the final desired shape. Independent claims are also included for: (i) a window produced by this method; (ii) a laminated window curved in two orthogonal directions of which at least one of the sheets present under umbrascopy a line of contrast in the inner zone.