Stock material or miscellaneous articles – Composite – Of quartz or glass
Patent
1995-05-30
1996-12-17
Ryan, Patrick
Stock material or miscellaneous articles
Composite
Of quartz or glass
428 34, 428 68, 428 76, 428192, 428412, 428437, 4284231, 4284256, 428911, 428913, 52308, 523091, B32B 900
Patent
active
055851886
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a pane, notably a pane used in the aeronautical sector.
The pane may be monolithic or laminated, of glass or of plastics material, or it may also be a composite pane composed of an assembly of rigid sheets, of glass and/or of plastics material, and of flexible sheets.
A composite pane used in the aeronautical sector is, commonly, composed of at least two sheets of thermally or chemically toughened glass, between which there is an intermediate sheet of plastics material which may, if desired, be composed of several plies or sheets.
When the pane is in the usual conditions of a high altitude flight it is subjected, on the one hand, to considerable differences of pressure between its two faces and, on the other hand, to also considerable differences of temperature between the median part and the peripheral part of the pane. Furthermore, it is also subjected to vibrational loadings. As indications, the pressure difference may reach 900 millibars and the temperature difference may reach approximately 70.degree. C. To these already high stresses there can be added stresses due, for example, to an impact in flight, in particular at low temperature, such as the strike of a bird, or other local stresses.
As a result of these particularly high loadings, such panes deteriorate with use after a greater or lesser period.
Solutions have already been proposed for reducing the risks of failure of the pane. One of the most common causes of failure is the difference in the coefficients of thermal expansion of the glass and of the intermediate sheet of plastics material which is, generally, of polyvinyl butyral. One solution consists of introducing a material having a low coefficient of thermal expansion into the marginal part of the pane, between the intermediate sheet and the glass. Another solution consists of placing a continuous film of a material of a difference nature having a lower modulus of elasticity between the intermediate sheet and the glass. These solutions may, however, lead to optical defects in the pane. There has also been proposed, in the document EP 508 864, an intermediate sheet of polyvinyl butyral composed of several plies, the plasticizer content of the plies in contact with at least one sheet of glass being higher than in the internal plies. This characteristic makes possible, also, a reduction and indeed an elimination of the known stresses leading to a cleavage of the glass, that is to say a rupture in a plane substantially parallel to the plane of the glass, notably when it is chemically toughened.
These panes of the earlier documents have exhibited, as a whole, improved properties. They have satisfactory working lives. Nevertheless, in certain cases, important precautions are necessary during the production of the pane.
The present invention overcomes these disadvantages.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a pane having the desired qualities of long life in the conditions of temperature and pressure to which a pane used in the aeronautical sector may be subjected.
The inventors have achieved this result by demonstrating the stresses to which the pane is subjected during manufacture and installation in the aircraft fuselage. The inventors have demonstrated that, in particular, during handling it was possible for the pane to be subjected to shocks or impacts creating micro-defects which, although not visible, could cause deterioration of the pane. The inventors have also determined the characteristics for overcoming these defects and have found a solution compatible with the demands of the aeronautics industry and offering the advantage of being, in addition, easy to carry out.
The invention concerns a pane, the edge face of which is at least partly covered by a strip or band.
In one of its aspects, the invention concerns a pane comprising at least one sheet of glass, the edge face of which is, at least partly, covered by a protective strip.
The material forming the strip according to this invention is chose
REFERENCES:
patent: 4321777 (1982-03-01), Sauret et al.
patent: 5082736 (1992-01-01), Bravet et al.
patent: 5279882 (1994-01-01), Daude et al.
Chaussade Pierre
Cheron Jean
Bahta Abraham
Ryan Patrick
Saint-Gobain Vitrage International
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