Glass windows mounted on the structure via fixing points

Abstract

The subject of the invention is: a monolithic or laminated glazing (1) bolted or clamped by a frame (4) which is itself bolted to a structure (3) or passes through said structure (3), characterized in that, in at least a portion of the edge of the glazing which has the greatest flexibility or the least rigidity in relation to the buckling phenomenon, the bolting is carried out by means of inserting at least one bolt (2) into a bushing (7) which is concentric with the bolt (2), or alternatively by inserting bushings (7) or pins (7), each bushing (7) or pin (7) being mounted without play on the glazing (1) or the frame (4) and on the structure (3) or passing through said structure (3); the use of this glazing (1) as an aeronautical glazing.

Description

Technical Field

[0001] The present invention relates to the field of bolted vehicle glazings (land, water or air vehicles) subjected to pressures (static or dynamic) which entail a risk of buckling. Static pressure here refers to the pressure exerted on the outside of the glazing of an aircraft, for example at a constant non-zero speed, while dynamic pressure refers to the pressure exerted on the outside of the glazing of an aircraft at varying speed. Buckling is defined as the reversal of the curvature of the glazing, usually towards the inside of the aircraft (or towards the cabin) under the effect of loads such as aerodynamic pressure. The buckling phenomenon is not relevant for pressurized aircraft glazings due to the low aerodynamic pressure from outside to inside, less than 0.1 bar, relative to cabin pressurization levels of more than 0.6 bar. Background Art

[0002] At present, the glazing is bolted directly or via a clamping frame of the glazing to or through the mounting structure (aircraft cabin, etc.) in order to keep the glazing fixed to the latter. Screws keep the glazing pressed against the structure. There may be a number of fixing points, for example, for a measuring of 1.2 m 2 glazings with more than 80 fixing points: this means that the screws are installed with play on the glazing or its clamping frame, so that the holes in this glazing or in this frame face the corresponding holes in the structure for the final tightening of the bolts.

[0003] Translation of the glazing is stopped by friction (under the screw head), and rotation creates stress on the body of the screw itself.

[0004] To prevent the risk of buckling, possibilities are to thicken the transparency and / or the frame to increase the stiffness of the glazing, and / or to increase the number of fixing points to strengthen the boundary conditions.

[0005] These possibilities raise a number of issues, the importance of which varies depending on the area of ​​use (ground / air), and these issues are as follows:

[0006] - Significant increase in weight: Thickening the transparent parts and increasing the number of fixings directly affect the weight of the glazing; this is particularly problematic in aviation applications;

[0007] - Increased installation time: increasing the number of fixings means longer replacement times and higher costs (in time and parts); in addition, increasing the number of fixing points increases the complexity of tightening (sequence) and the repeatability of boundary conditions;

[0008] - Reduced resistance at the edges: drilled holes are obvious stress concentration areas; increasing the number of drilled holes means increasing stress; moreover, in the event of a collision (birds, pedestrians, animals, projectiles, etc.), a thicker (harder) transparent piece will transmit more stress to the attachment: the edges of the mounting structure and the edges of the glazing (frame) will have to be dimensioned accordingly (heavier). Summary of the invention

[0009] The invention consists in defining specific fixing points (rigid fixing) combining the traditional function of keeping the glazing pressed against the structure with anti-translation and anti-rotation functions to locally enforce the boundary conditions.

[0010] To this end, the subject of the invention is a monolithic or laminated glazing, bolted or clamped by a frame itself bolted to or through a structure, characterized in that, in at least a portion of the periphery of the glazing having the greatest flexibility or the least rigidity with respect to buckling phenomena, the bolting is carried out by means of at least one bolt inserted in a bushing concentric with the bolt, or alternatively by the insertion of bushings or pins, each of which is mounted without play on the glazing or on the frame and on or through the structure.

[0011] Monolithic glazing consists of a single transparent sheet of mineral glass, such as soda lime, aluminosilicate, borosilicate, etc., which may be heat tempered or chemically strengthened, or of polymer materials, such as polymethyl methacrylate (PMMA), polycarbonate (PC), polyurethane (PU), ionomer resins, etc.

[0012] Laminated glazing is composed of several such transparent mineral glass sheets or polymer materials bonded in pairs by an adhesive interlayer such as polyvinyl butyral (PVB), thermoplastic polyurethane (TPU), ethylene vinyl acetate (EVA), etc.

[0013] When a bushing is used, it is inserted without play into a corresponding hole in the glazing or its clamping frame. The screw of a bolt concentric with the bushing can be inserted into the bushing or, on the other hand, the bushing is independent of any screw, any screw-nut (bolt) assembly. Like the pin, the bushing is also inserted without play into a corresponding hole in the mounting structure, possibly while passing through the structure.

[0014] The rigid fixing points (without play) are specifically defined (number and location) according to the parameters of the use case (size / shape / thickness of the glazing, structural rigidity, pressure distribution, material implemented, etc.) to avoid any static uncertainty and maintain the ability of the product to be mounted without stress. The number of bushings and pins, whether the screws pass through the bushings, the shape of the bushings and pins used (see below for details), the presence or absence of shoulders on the bushings / pins, and the use of combinations of different bushings and / or pins will also be adapted to these parameters of the use case.

[0015] The rigid fixing point according to the invention is advantageous for glazings which are subject to stresses which may cause buckling and for which it is desirable to limit the weight and / or to simplify the implementation, installation and / or replacement.

[0016] The present invention, by combining a few rigid fixing points in the least rigid portion of the perimeter of the glazing where buckling may begin with known fixing points with clearance, makes it possible to reduce the total number of fixing points of the glazing without changing its behavior with respect to buckling, or to maintain the total number of fixing points by reducing or eliminating buckling.

[0017] Preferably, the bushing or the pin consists of a mechanically resistant, rigid material, such as a metal or a composite material including reinforcing fillers and / or fibres.

[0018] Preferably, at least one bushing has the geometry of a cylindrical pipe segment.

[0019] Preferably, at least one pin is cylindrical and solid.

[0020] Preferably, at least one pin is tapered and solid.

[0021] Preferably, at least one bushing or at least one pin has a shoulder, in particular a surface for pressing against and resting against the structure.

[0022] Another subject of the invention is the use of the above-described glazing, such as glazings subjected to static or dynamic stress, in particular aeronautical glazings, and especially airplane or helicopter glazings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is illustrated in the accompanying drawings. The figures are schematic cross-sectional views of glazing mounted on a structure subjected to static and / or dynamic pressure, in particular an aircraft glazing.

[0024] [ Figure 1 ]and[ Figure 2 ] represents a known stationary glass window.

[0025] [ Figure 3 ]and[ Figure 4 ] represents a known glass window in a flexed position.

[0026] [ Figure 5 ]and[ Figure 6 ] represents the first known solution to the buckling problem.

[0027] [ Figure 7 ]and[ Figure 8 ] represents the first type of embodiment according to the present invention.

[0028] [ Fig. 9 ]and[ Fig.10] represents the second type of embodiment according to the present invention. DETAILED DESCRIPTION

[0029] refer to Figure 1 , the glass window 1 of the aircraft is clamped by a frame 4, which is bolted to a structure 3 (cabin) by means of bolts 2, which are composed of screws and nuts. Washers 5 separate the screw heads from the upper part of the clamping frame 4 of the glass window 1. A watertight and airtight seal 6 separates the lower part of the frame 4 from the structure 3.

[0030] In view of the large number of bolting points of the aircraft glazing 1 , the screws of the bolts 2 are inserted with play into the holes of the frame 4 so that the holes of the frame 4 coincide with the corresponding holes of the structure 3 until the end of the bolting, that is to say including the last bolt to be tightened.

[0031] Figure 2 and Figure 1 The difference is that there is no intermediate frame 4, this time the glass window 1 itself is provided with holes and is bolted directly to the cabin 3 and passes through the cabin 3. Figure 1 For the same reason, the screw of bolt 2 is inserted into the hole of glass window 1 with clearance.

[0032] Figure 1 and Figure 2 The installed glass windows are respectively represented as being in Figure 3 and Figure 4 The translation is stopped by friction under the screw head of the frame 4 of the glazing 1. The rotation generates stresses on the body of the screw itself.

[0033] To limit (reduce, eliminate) buckling, Figure 1 and Figure 2 The installed glazing can be modified by making them thicker, respectively as Figure 5 and Figure 6 The resulting increased weight is obviously disadvantageous, especially in aerospace applications.

[0034] According to a first embodiment of the present invention, Figure 1 and Figure 2 The installed glazing has one or more (not all, usually a few, limited number) modified bolt fixing points, such as Figure 7 , Figure 8 The bushing 7 is inserted without play into the hole of the frame 4 or the glass window 1 on the one hand and into the hole of the cabin 3 on the other hand. The screw of the bolt 2 can be as Figure 7 and Figure 8 , but may well not be inserted into bushing 7.

[0035] According to a second embodiment of the present invention, Figure 1 and Figure 2 The installed glazing has one or more (not all, usually a few, limited number) modified bolt fixing points, such as Fig. 9 , Fig.10 . The cylindrical and conical pins 7 (solid) are respectively inserted without play into the holes of the frame 4 of the glass window 1. The latter is thus also conical.

[0036] and Fig.10 Same as pin 7, Figure 8 The bushing 7 has a shoulder portion, which is used to press and rest against the bottom surface of the nacelle 3 .

[0037] According to the present invention, at the portion of the periphery of the glass window having a lower rigidity, that is, the portion where the buckling begins, the Figure 7 , 8 , 9 and 10 modify a limited number of bolt attachment points sufficient to reduce / eliminate buckling.

Claims

1. An assembly comprising a monolithic or laminated glazing (1) and a structure, wherein the monolithic or laminated glazing (1) is (a) bolted to or through the structure, or (b) clamped by a frame (4), the frame (4) itself being bolted to or through the structure (3), wherein: In at least a portion of the periphery of the glazing which has the greatest flexibility or the least rigidity in relation to the buckling phenomenon, the bolting is performed by (i) inserting at least one bolt (2) into a bushing extending through the structure and concentric with the bolt (2), or (ii) inserting a solid pin without a bolt, the solid pin extending through the structure and wherein each bushing or each solid pin is mounted without play on the glazing (1) or on the frame (4) and passes through the structure (3), the bushing or the solid pin being made of a mechanically resistant and rigid material.

2. The assembly according to claim 1, characterized in that The rigid material is metal.

3. The assembly according to claim 1, characterized in that The rigid material is a composite material comprising reinforcing fillers and / or fibers.

4. The assembly according to claim 1, characterized in that At least one bushing has the geometry of a cylindrical pipe segment.

5. The assembly according to claim 1, characterized in that At least one of the solid pins is cylindrical and solid.

6. The assembly according to claim 1, characterized in that At least one of the solid pins is tapered and solid.

7. The assembly according to claim 1, characterized in that At least one bushing or at least one of the solid pins has a shoulder.

8. The assembly according to claim 7, characterized in that The shoulder is a surface for supporting and resting the structure (3).

9. A method of using an assembly according to any one of claims 1 to 8, wherein the glazing (1) is used as a glazing subject to static or dynamic pressure.

10. The method according to claim 9, characterized in that The glass window is an aviation glass window.

11. The method according to claim 10, characterized in that The glazing is an aircraft or helicopter glazing.

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