AERONAUTICAL GLAZING WORKING WITH A MEMBRANE OF ENHANCED STRUCTURAL PERFORMANCE AND AIRCRAFT COMPRISING IT

Abstract

----- AEROSPACE GLAZING WORKING AS A MEMBRANE WITH ENHANCED STRUCTURAL PERFORMANCE AND AIRCRAFT COMPRISING THEREOF The invention relates to an aerospace glazing (100) working as a membrane comprising a frame carrying an external ply (102) and at least two structural plyes (103, 104), the sum of the thicknesses of the structural ply being designated d, a flange (107a, 107b) being formed at the periphery of each structural ply (103, 104), each structural ply being fixed to its corresponding flange (107a, 107b) by means of inserts (108a, 108b, 109a, 109b), the frame being constituted by an external retainer (111) and an internal counter-retainer (112), the frame being configured to be fixed to an aerospace structure (115) by one of the forming elements the chassis,The thickness of the structural ply closest to the frame element configured to be attached to the aircraft structure is less than or equal to 40% of the thickness d when the glazing comprises two structural plyes, and less than or equal to the thickness d divided by the number of structural plyes when the glazing comprises more than two structural plyes. Figure to be published: Figure 2,

Description

Title of the invention: AERONAUTICAL GLAZING WORKING IN A HIGH-PERFORMANCE MEMBRANE INCREASED STRUCTURAL AND AIRCRAFT COMPRISING IT

[0001] The invention relates to a membrane-based glazing intended for use in the aeronautical field, having increased structural performance.

[0002] In aeronautical construction, membrane-operated glazing corresponds to structural and glazing designs for which the membrane loads induced by the pressurization of the aircraft at high altitude are transmitted between the aircraft structure and the glazing. Indeed, due to the low atmospheric pressure at high altitude, it is customary in commercial aviation to pressurize the cabin for the comfort of pilots and passengers. Conversely, according to other mechanical construction strategies, the glazing can be spared membrane forces by the use of rigid aircraft structures and / or flexible attachments, such as, for example, in the case of pinched technologies incapable of transmitting forces in the plane of the external surface of the aircraft at the structure-glazing interfaces.Commonly used in the aeronautics field, working glazing is designed to withstand without failure (breakage, finning, delamination, etc.) the tangential tensile forces generated by the pressurization of the aircraft.

[0003] Usually, membrane-operated glazing comprises a frame carrying at least three plies, also called sheets for laminated glazing, bonded together by flexible transparent adhesives. At least two of these plies are structural plies, carrying the membrane forces. In the prior art, only two structural plies at most are implemented and they are of substantially equal thicknesses. Membrane-operated glazing may consist of structural plies of glass, poly(methyl methacrylate) (PMMA) or polycarbonate (PC). The external non-membrane-operated ply is generally made of glass and serves to manage the interface with the particularly aggressive external environment (abrasion by dust, windshield wipers, anti-icing heating, management of electrostatic charges).Compatibility between the outer glass and the structural plies is difficult to manage and can in particular lead to early delaminations during the use of the glazing. For this reason, when the lifetime constraints of the glazing are taken into account, the use of glazing in which all the plies are made of glass is often preferred.

[0004] The transmission of membrane forces to the structural folds is not done directly but via intermediate parts called heels. The frame is generally made up of an external retainer (also called an ice press) and of an internal counter-retainer fixed to the external retainer by a bolt extending transversely to the thickness of the glazing and passing through the heels, the retainer, generally the external retainer, being itself fixed to the aeronautical structure. The shank of the bolt screw passes through the external retainer, the inserts, the heels, optionally a shim, the internal counter-retainer, the whole being retained between the head of the bolt screw and the bolt nut, both located on either side of the sandwich thus formed. The forces are then transmitted from the heels to the structural plies by gluing inserts connecting the heels and the structural plies.

[0005] The inserts ensure the "fail safe" function, guaranteeing that the glazing is held in place in the event of breakage of one or both structural plies ("full fail safe"). The forces are transmitted through the inserts, by traction and compression.

[0006] The intersection between the transversely extending bolt and the external retainer constitutes the point of maximum force transfer. The inserts closest to this point are the most loaded in tension. Conversely, the insert(s) furthest from this point are loaded in compression.

[0007] The disadvantage of this embodiment according to the state of the art is that it does not allow significant forces to be transmitted due to the limit loads of the structural bonds on the glass plies. In particular, the conventional arrangements cannot be used on large aircraft with membrane glazing because the intensity of the membrane forces increases with the characteristic diameter of the aircraft. Furthermore, the limitations of the prior art require the use of less reliable structural plastic-based glazing for these aircraft.

[0008] The invention proposes to overcome these drawbacks of the state of the art and to ensure a better distribution of forces. The thickness of the structural ply closest to the frame element configured to be fixed to the aeronautical structure is less than or equal to 40% of the thickness d, d representing the sum of the thicknesses of the structural plies, when the glazing comprises two structural plies and less than or equal to the thickness d divided by the number of structural plies of the glazing, when the glazing comprises more than two structural plies. The present invention proposes to implement two structural plies of different thicknesses or more than two structural plies of the same thickness or of different thicknesses. Depending on the frame element fixed to the aeronautical structure, the maximum force transfer point may be located on the external side of the glazing or on the internal side of the glazing.When the point of maximum force transfer is located on the external side of the glazing, the frame element fixed to the aeronautical structure is the external retainer. When the point of maximum force transfer is located on the internal side of the glazing, the frame element fixed to the aeronautical structure is an internal retainer located on the internal part of the glazing. The . retainer is fixed to a counter-retainer by at least one fixing element extending transversely to the thickness of the glazing and passing through the beads. In the case where the retainer is external, the counter-retainer is an internal belt and in the case where the retainer is internal, the counter-retainer is an external cover. In the prior art, the two internal inserts of the glazing being approximately in the middle of the structural block, they transmit only little force while the insert near the point of maximum force transfer is very heavily loaded. By reducing the thickness of the structural ply closest to the point of maximum force transfer, the second and third inserts are brought closer to the first, which makes it possible to transfer part of the forces transmitted by the first insert to the second and third inserts and increases the permissible loads of the assembly for an identical thickness and total mass of glazing.

[0009] In the present application, the term “fold” is understood as designating a sheet of laminated glazing.

[0010] The term “structural ply” is used to designate a ply that provides mechanical resistance.

[0011] The terms "interior", "internal", respectively "exterior", "external" are to be understood in the present application as referring to the interior, respectively to the exterior, of the aircraft in which the membrane-working glazing of the invention is intended to be installed.

[0012] The subject of the invention is an aeronautical glazing comprising a frame carrying an external ply and at least two structural plies, two successive plies being secured by an interlayer adhesive, the sum of the thicknesses of the structural plies being designated d, a heel being formed at the periphery of each structural ply, each structural ply being fixed to its corresponding heel by means of inserts fixed respectively at one end at the edge of the external surface and at the edge of the internal surface of each structural ply and at the other end to the external surface and to the internal surface of the corresponding heel, the frame being constituted on the one hand by an external retainer, respectively an internal retainer, and on the other hand by an internal counter-retainer, respectively an external counter-retainer, the counter-retainer being fixed to the retainer by at least one fixing element extending transversely to the thickness of the glazing and passing through the heels,the frame thus sandwiching the heels and inserts of the structural plies to hold the structural plies, with the outer ply flush with the outer surface of the outer retainer, respectively of the outer counter-retainer, the frame being configured to be fixed to an aeronautical structure by one of the elements forming the frame, characterized in that the thickness of the structural ply closest to the frame element configured to be fixed to the aeronautical structure is less than or equal to 40% of the thickness d when the glazing comprises two structural plies and is less than or equal to the thickness d divided by the number of , structural folds of the glazing when the glazing comprises more than two structural folds.

[0013] Thus, the inserts are brought closer to the frame element configured to be fixed to the aeronautical structure defining the maximum force transfer point, allowing a better distribution of the forces between the inserts. By reducing the forces carried by the most loaded insert, the admissible loads of the assembly for an identical thickness and total mass of glazing are increased. The thinner this ply, the lower the forces transmitted by the most loaded insert in the event of rupture of a structural ply.

[0014] Preferably, the inserts extend over the entire surface of the heel and are therefore also crossed by the fixing element. However, the invention is not limited in this respect and it may be envisaged that the fixing element only passes through the heels, and that the forces are retransmitted from the heels to the inserts then not crossed by the fixing element.

[0015] According to one embodiment, the thickness of the structural plies increases from the structural ply closest to the frame element configured to be fixed to the aeronautical structure. This has the advantage of even better sharing the forces between the inserts closest to the point of maximum force transfer and of increasing the bending stiffness of the glazing by means of the thickest glass.

[0016] According to one embodiment, the frame comprises two plies, the thinner being the structural ply closest to the frame element configured to be attached to the aeronautical structure.

[0017] According to one embodiment, the frame comprises three plies, the thinnest being the structural ply closest to the frame element configured to be fixed to the aeronautical structure, and thus the forces are transmitted by six inserts instead of four. This makes it possible to position a thinner glass close to the point of maximum force transfer, with the same advantages as previously. In addition, the forces are transmitted by six inserts instead of four.

[0018] According to one embodiment, the frame comprises three plies of identical thicknesses.

[0019] According to one embodiment, the folds are made of glass, which makes it possible to limit or to eliminate early delamination during the use of the glazing and thus increase the service life of the glazing. Preferably, the glasses are thermally toughened or preferably chemically strengthened. Preferably, the glasses are one of a soda-lime mineral glass or a mineral, borosilicate or aluminosilicate glass.

[0020] According to one embodiment, the external retainer, preferably made of aluminum, is fixed to the aeronautical structure, for example by bolting or gluing.

[0021] According to one embodiment, the internal retainer, preferably made of aluminum, is fixed to the aeronautical structure, for example by bolting or gluing.

[0022] According to one embodiment, the glazing comprises a first seal between the external retainer, respectively the external counter-retainer, and the external ply, one branch of which extends peripherally over the insert fixed to the edge of the external surface of the outermost structural ply and, where appropriate, a second seal between the internal retainer, respectively the internal counter-retainer, and the inner edge of the innermost structural ply and of the insert fixed thereon.

[0023] According to one embodiment, the glazing comprises a thickness shim between the internal retainer and the insert fixed at the edge of the inner surface of the innermost structural ply, making it possible to best adjust the shape of the glazing to that of the structure.

[0024] According to one embodiment, the glazing comprises a flexible outer strip allowing the inserts to be extended in order to improve the homogeneity of transmission of forces between the heels and the glass.

[0025] According to one embodiment, the at least one fastening element is a bolt.

[0026] The present invention also relates to an aircraft equipped with at least one aeronautical glazing as described above.

[0027] To better illustrate the object of the present invention, particular embodiments will now be described, for informational and non-limiting purposes, in conjunction with the appended drawings.

[0028] On the drawings:

[0029] [Fig.l] is a schematic sectional view of a glazing working in membrane according to the state of the art.

[0030] [Fig.2] is a schematic sectional view of a glazing according to a first method of rea lization.

[0031] [Fig.3] is a schematic sectional view of a glazing according to a second method of realization.

[0032] [Fig.4] is a schematic sectional view of a glazing according to a third method of realization.

[0033] [Fig.5] is a schematic sectional view of a glazing according to a fourth method of realization.

[0034] [Fig.6] is a schematic sectional view of a glazing according to a fifth method of realization.

[0035] [Fig.7] is a schematic sectional view of a glazing according to a sixth method of rea lization.

[0036] [Fig.l] represents the state of the art for a glazing working in membrane 1, which comprises a frame carrying an external ply 2 and at least two structural plies 3, 4, with an interlayer 6a between the external ply 2 and the outermost structural ply 3 and an interlayer 6b between the two structural plies 3, 4. Conventionally, the interlayers 6a, 6b are made of thermoplastic polymer, poly(vinyl butyral) (PVB), poly thermoplastic urethane (TPU), ethylene vinyl acetate (EVA) or ionomer resin, and secure the different plies of the glazing 1 together. Typically, the outer ply 2 has a thickness of 2 to 5 mm. The sum of the thicknesses of the structural plies 3, 4 is designated d.

[0037] A heel 7a, 7b is formed at the periphery of each structural ply 3, 4, each structural ply 3, 4 being fixed to its corresponding heel 7a, 7b by means of inserts 8a, 8b, 9a, 9b fixed respectively, at one end, at the edge of the outer surface and at the edge of the inner surface of each structural ply 3, 4 and, at the other end, to the outer surface and to the inner surface of the corresponding heel 7a, 7b. The inserts 8a, 8b, 9a, 9b are fixed to the structural plies 3, 4 by an adhesive 19. The membrane forces are transmitted from the heels 7a, 7b to the structural plies 3, 4 via the inserts 8a, 8b, 9a, 9b connecting each heel 7a, 7b to its corresponding structural ply 3, 4. Conventionally, the heels 7a, 7b and the inserts 8a, 8b, 9a, 9b are made of glass fiber composites or more rarely of titanium. Other materials, in particular other composites, may also be envisaged within the scope of the invention.

[0038] An outer strip 18a, 18b of molded, flexible material, polyurethane, thermoplastic elastomer, optionally silicone or poly(vinyl butyral) (PVB), is formed between the edge of each structural ply 3, 4 and its corresponding heel 7a, 7b.

[0039] The chassis is constituted on the one hand by an external retainer 11 (also called an ice press), generally made of aluminum, and on the other hand by a counter-retainer 12 (or belt) fixed to the external retainer 11 by a fixing element 14, conventionally a bolt comprising a screw 14a and a nut 14b. Thus, the chassis sandwiches the heels 7a, 7b and the inserts 8a, 8b, 9a, 9b of the structural plies 3, 4 to maintain the structural plies 3, 4 with the external ply 2 flush with the external surface of the external retainer 11. By way of illustration and not limitation for the embodiment shown, the chassis is fixed to the aeronautical structure 15 at the level of the external retainer 11, by means of the bolt B.Consequently, the frame element fixed to the aeronautical structure being the external retainer, the maximum force transfer point 20 is located on the external side of the glazing, such that the insert 8a fixed at the edge of the external surface of the external structural ply 3 is the most loaded in tension, while the tensile loads are low on the inserts 8b and 9a fixed at the edge of the internal surface of the external structural ply 3 and at the edge of the external surface of the internal structural ply 4, and the insert 9b fixed at the edge of the internal surface of the internal structural ply 4 is compressed (or loaded in compression).

[0040] When there is rupture of the external structural ply 3, the mechanical support is ensured at the level of the internal structural ply 4 by the inserts 9a, 9b fixed on the internal structural ply. 4. The forces pass through the insert 9a fixed to the outer surface edge end of the internal structural ply 4 by traction and through the insert 9b fixed to the inner surface edge end of the internal structural ply 4 by compression. The forces are significant due to the leverage effect due to the distance of the maximum force transfer point 20 from the two inserts 9a and 9b.

[0041] The glazing 1 comprises a first seal 16a located between the external retainer 11 and the external ply 2, one branch of which extends peripherally over the insert 8a fixed to the outer surface edge of the outermost structural ply 3 and a second seal 16b between the internal counter-retainer 12 and the inner edge of the innermost structural ply 4 and the insert 9b fixed thereon. Conventionally, the seals are made of polysulfide, in particular PR 1440 M, based on polysulfide liquid rubber and a manganese-based accelerator and having excellent adhesion to aluminum, titanium, steel and many other materials.

[0042] [Fig.2] represents a first embodiment of the invention.

[0043] In this embodiment, elements analogous to the elements described in connection with [Fig.l] above for the state of the art will bear the same reference number increased by 100 when they are of the same structure, and will not be described in more detail.

[0044] The membrane-operated glazing 100 comprises a frame carrying an outer ply 102 and at least two structural plies 103, 104, with an interlayer 106a between the outer ply 102 and the outermost structural ply 103 and an interlayer 106b between the two structural plies 103, 104. Conventionally, the interlayers 106a, 106b are made of thermoplastic polymer, poly(vinyl butyral) (PVB), thermoplastic polyurethane (TPU), ethylene-vinyl acetate (EVA) or ionomer resin, and secure the different plies of the glazing 1 together.

[0045] The total thickness of the structural plies is similar to the prior art but the structural plies 103, 104 have a different thickness, the thinnest structural ply 103 being the structural ply closest to the frame element 111 configured to be attached to the aeronautical structure 115. The thickness of the structural ply 103 is less than or equal to 40% of the thickness d, d representing the sum of the thicknesses of the structural plies.

[0046] The intersection between the fixing element 114 and the external retainer 111 represents the maximum force transfer point 120. The thickness of the fold 103 closest to this point being thinner than in the prior art, it follows that the inserts 108b and 109a are also brought closer to the maximum force transfer point 120 and become more capable of transmitting the membrane forces, which reduces the forces carried by the insert 108a which nevertheless remains the most loaded. The inserts 108b and 109a are capable of supporting greater tensile loads, whereas in the prior art, the Inserts 8b and 9a support few tensile loads and more compressive loads, allowing for better distribution of forces. The reduction in forces carried by insert 108a makes it possible to increase the permissible loads of the assembly for an identical thickness and total mass of glazing.

[0047] Furthermore, in the event of rupture of a single structural ply, the forces pass through only two inserts, one in compression and the other in tension. The further the insert in tension is from the maximum force transfer point 120, the greater the forces to be borne by lever arm amplifying effect, that is to say that in the event of rupture of the external structural ply 103 closest to the maximum force transfer point 120, the insert in tension is consequently further from the maximum force transfer point 120 and the forces to be borne are greater. In accordance with this embodiment, the reduction in the thickness of the external structural ply 103 makes it possible to reduce the forces transmitted by the insert 109a fixed at the edge of the external surface of the internal structural ply 104 which becomes the most loaded in the event of rupture of the external structural ply 103.

[0048] The other elements are otherwise identical to those described for [Fig.l] and will not be described in further detail here.

[0049] [Fig.3] represents a glazing working in membrane 200 according to a second embodiment.

[0050] Elements of the same structure as the first embodiment will bear the same reference number increased by 100, and will not be described in further detail here.

[0051] The difference between the second embodiment and the first embodiment lies in the fact that the chassis carries three structural plies 203, 204, 205 of identical size. Accordingly, this embodiment comprises a first interlayer 206a between the outer ply 202 and the outermost structural ply 203, a second interlayer 206b between the two outermost structural plies 203, 204 and a third interlayer 206c between the two innermost structural plies 204, 205. In the same way, an additional heel 207c is formed at the periphery of the additional structural ply 205, this structural ply 205 being fixed to its corresponding heel 207c by means of inserts 210a, 210b fixed respectively at one end at the edge of the outer surface and at the edge of the inner surface of the structural ply 205 and at the other end to the outer surface and to the inner surface of the corresponding heel 207c.The membrane forces are transmitted from the heels 207a, 207b, 207c to the structural plies 203, 204, 205 via the inserts 208a, 208b, 209a, 209b, 210a, 210b connecting each heel 207a, 207b, 207c to its corresponding structural ply 203, 204, 205. In the same way, an additional outer strip 218c is formed between the additional structural ply edge 205 and its corresponding additional heel 207c.

[0052] In this embodiment, the thickness of the structural ply 203 closest to the frame element configured to be fixed to the aeronautical structure, i.e. the structural ply 203 closest to the external retainer 211, is less than or equal to the thickness d divided by 3, 3 representing the number of structural plies of the glazing 200.

[0053] As for the first embodiment, this makes it possible to position a thinner fold 203 close to the maximum force transfer point 220, with the same advantages as previously. In addition, the membrane forces are transmitted by six inserts 208a, 208b, 209a, 209b, 210a, 210b instead of four for the first embodiment.

[0054] [Fig.4] represents a glazing working in membrane 300 according to a third embodiment.

[0055] Elements of the same structure as the second embodiment will bear the same reference number increased by 100, and will not be described in further detail here.

[0056] The difference between the third embodiment and the second embodiment lies in the fact that the thickness of the three structural plies 303, 304, 305 increases from the structural ply 303 closest to the external retainer 311 configured to be fixed to the aeronautical structure 315.

[0057] Thus, the structural ply 303 closest to the maximum force transfer point 320 is the thinnest and the most distant structural ply 305 is the thickest. This makes it possible to share the membrane forces more between the inserts, due to the bringing of the inserts 308b and 309a closer to the maximum force transfer point 320 and to increase the bending stiffness of the glazing by means of the thickest ply 305.

[0058] [Fig.5] represents a glazing working in membrane 400 according to a fourth embodiment.

[0059] Elements of the same structure as the third embodiment will bear the same reference number increased by 100, and will not be described in further detail here.

[0060] The difference between the fourth embodiment and the third embodiment lies in the fact that the frame is fixed to the aeronautical structure 415 by means of the internal retainer 413, preferably made of aluminum. In addition, the internal counter-retainer 312 present in the third embodiment is eliminated and a shim 417 can be inserted between the internal retainer 413 and the insert 409b fixed at the edge of the inner surface of the innermost structural ply 404. The shim 417 makes it possible to best adjust the shape of the glazing 400 to that of the aeronautical structure 415. The external counter-retainer 411 is an external cover.Due to the attachment to the aeronautical structure 415 by the internal retainer 413, the maximum force transfer point 420 is moved towards the internal part of the glazing 400, this point being located at the intersection between the attachment element 414 and the element forming the frame attached to the aeronautical structure 415, i.e. the internal retainer 413 in this . embodiment. In this embodiment, the chassis carries two structural plies of different thicknesses, the thickness increasing from the structural ply closest to the chassis element attached to the aeronautical structure 415, i.e. the innermost structural ply 404 is the thinnest.

[0061] Conversely to the first embodiment, the thickness of the structural ply 404 is less than or equal to 40% of the thickness d, d representing the sum of the thicknesses of the structural plies. This makes it possible to bring the inserts 409a and 408b closer to the maximum force transfer point 420, such that they become more capable of transmitting the membrane forces. This configuration makes it possible to reduce the forces carried by the insert 409b closest to the maximum force transfer point 420, the insert 409b nevertheless remaining the most loaded. The inserts 409a and 408b are capable of supporting greater tensile loads. The reduction in the forces carried by the insert 409b makes it possible to increase the permissible loads of the assembly for an identical thickness and total mass of glazing.

[0062] [Fig.6] represents a glazing working in membrane 500 according to a fifth embodiment.

[0063] Elements of the same structure as the fourth embodiment will bear the same reference number increased by 100, and will not be described in further detail here.

[0064] The difference between the fifth embodiment and the fourth embodiment lies in the fact that the chassis carries three structural plies 503, 504, 505 of the same thickness.

[0065] In this embodiment, the thickness of the structural ply 505 closest to the frame element configured to be fixed to the aeronautical structure 515, i.e. the structural ply 505 closest to the internal retainer 513, is less than or equal to the thickness d divided by 3, 3 representing the number of structural plies of the glazing 500.

[0066] This makes it possible to position a thinner fold 505 close to the maximum force transfer point 520, with the same advantages as previously. In addition, the membrane forces are transmitted by six inserts 510b, 510a, 509b, 509a, 508b, 508a, in order of proximity to the maximum force transfer point 520, instead of four for the fourth embodiment.

[0067] [Fig.7] represents a glazing working in membrane 600 according to a sixth mode of realization.

[0068] Elements of the same structure as the fifth embodiment will bear the same reference number increased by 100, and will not be described in further detail here.

[0069] The difference between the sixth embodiment and the fifth embodiment lies in the fact that the thickness of the three structural plies 605, 604, 603 increases from the structural ply 605 closest to the configured internal retainer 613 to be fixed to the aeronautical structure 615.

[0070] Thus, the structural ply 605 closest to the maximum force transfer point 620 is the thinnest and the most distant structural ply 603 is the thickest. This makes it possible to share the membrane forces more, due to the proximity of the inserts 610a and 609b to the maximum force transfer point 620.

[0071] Furthermore, the shim 617 can be glued to the innermost heel 607c, which makes it possible to reduce the load applied by the screw in the hole of this heel 607 which is the most loaded. This makes it possible to further asymmetrize the thicknesses of the structural plies 603, 604, 605.

[0072] This configuration is also particularly advantageous with respect to bird impact at high temperature. During a bird impact, the innermost ply is naturally the most stressed due to the convex curvature. This tendency decreases and disappears when the shear lamination interlayer allows the transmission of forces between the structural plies to be decorrelated. If the decorrelation were total, with identical curvature for all the plies, it is the thickest ply that would become the most stressed.

[0073] Thus, for the third embodiment, the internal ply 305 is both the thickest and the most internal, which makes it the weakest ply. Conversely, for partial decoupling of the structural plies by shearing of the interlayers (which is observed all the more when the interlayers are thick and warm, and also constitutes the worst case with regard to resistance to bird impact), the thinness of the internal ply makes it possible to reduce its loading level. The fourth, fifth and sixth embodiments are therefore more resistant to bird impact than the third embodiment, which is itself more resistant than the second, more flexible embodiment.

[0074] By applying a structural glass significantly thinner than the sum of the structural glasses, the bonded inserts work in a more balanced manner, which makes it possible to increase the admissible forces for this type of attachment without weighing down the glazing.

[0075] This provides access to aircraft with higher membrane loading levels than are usually available. In particular, larger aircraft have higher membrane stress levels.

[0076] This makes it possible to use glazings in which all the structural plies are made of glass, whereas the limitations of the prior art required the use of glazing based on less reliable structural plastics for these aircraft.

[0077] It is clearly understood that the invention is not limited to the specific shapes shown, in particular with regard to the heels, the retainer, the counter-retainer and that the person skilled in the art will know how to adapt the invention according to the aeronautical structure receiving a glazing according to the invention. Likewise, the person skilled in the art will understand that the presence of shims, when shown, is not necessarily necessary, or on the contrary, when not shown, may be necessary to adapt the glazing of the invention to a particular aeronautical structure. Furthermore, even if it is desirable, the presence of an external band on the periphery of the glazing is not obligatory within the framework of the invention.

[0078] Finally, although a bolt has been described and shown for fixing the glazing, other fixing elements, such as gluing, can be envisaged within the scope of the invention.

Claims

1. Claims Aeronautical glazing (100; 200; 300; 400; 500; 600) comprising a frame carrying an external ply (102; 202; 302; 402; 502; 602) and at least two structural plies (103, 104; 203, 204, 205; 303, 304, 305; 403, 404; 503, 504, 505; 603, 604, 605), two successive plies being secured by an interlayer adhesive (106a, 106b; 206a, 206b, 206c; 306a, 306b, 306c; 406a, 406b; 506a, 506b, 506c; 606a, 606b, 606c), the sum of the thicknesses of the structural plies being designated d, a heel (107a, 107b; 207a, 207b, 207c; 307a, 307b, 307c; 407a, 407b; 507a, 507b, 507c; 607a, 607b, 607c) being formed at the periphery of each structural ply (103, 104; 203, 204, 205; 303, 304, 305; 403, 404; 503, 504, 505; 603, 604, 605), each structural ply being fixed to its heel (107a, 107b; 207a, 207b, 207c; 307a, 307b, 307c; 407a, 407b; 507a, 507b, 507c; 607a, 607b, 607c) corresponding by means of inserts (108a, 108b, 109a, 109b; 208a, 208b, 209a, 209b, 210a, 210b;308a, 308b, 309a, 309b, 310a, 310b; 408a, 408b, 409a, 409b; 508a, 508b, 509a, 509b, 510a, 510b; 608a, 608b, 609a, 609b, 610a, 610b) fixed respectively at one end to the outer surface edge and to the inner surface edge of each structural ply and at the other end to the outer surface and to the inner surface of the corresponding heel, the frame being constituted on the one hand by an external retainer (111; 211; 311), respectively an internal retainer (413; 513; 613), and on the other hand by an internal counter-retainer (112; 212; 312), respectively an external counter-retainer (411; 511; 611), the counter-retainer (112; 212; 312; 411; 511; 611) being fixed to the retainer (111; 211; 311; 413; 513; 613) by at least one fixing element (114; 214; 314; 414; 514; 614) extending transversely to the thickness of the glazing and passing through the heels (107a, 107b; 207a, 207b, 207c; 307a, 307b, 307c; 407a, 407b; 507a, 507b, 507c;607a, 607b, 607c), the chassis thus sandwiching the heels (107a, 107b; 207a, 207b, 207c; 307a, 307b, 307c; 407a, 407b; 507a, 507b, 507c; 607a, 607b, 607c) and the inserts (108a, 108b, 109a, 109b; 208a, 208b, 209a, 209b, 210a, 210b; 308a, 308b, 309a, 309b, 310a, 310b; 408a, 408b, 409a, 409b; 508a, 508b, 509a, 509b, 510a, 510b; 608a, 608b, 609a, 609b, 610a, 610b) of the structural plies (103, 104; 203, 204, 205; 303, 304, 305; 403, 404; 503, 504, 505; 603, 604, 605) to maintain the structural plies, with the outer ply (102; 202; 302; 402; 502; 602) flush with the external surface of the external retainer (111; 211; 311), respectively of the external counter-retainer (411; 511; 611), the frame being configured to be fixed to an aeronautical structure (115; 215; 315; 415; 515; 615) by one of the elements forming the frame, characterized in that the thickness of the structural ply closest to the frame element configured to be fixed to the aeronautical structure is less than or equal to 40% of the thickness d when the glazing comprises two structural plies and is less than or equal to the thickness d divided by the number of structural plies of the glazing when the glazing comprises more than two structural plies.

2. Aeronautical glazing according to claim 1, characterized in that the thickness of the structural plies increases from the structural ply closest to the frame element configured to be fixed to the aeronautical structure.

3. Aeronautical glazing according to claim 2, characterized in that the frame comprises two plies, the thinnest being the structural ply closest to the frame element configured to be fixed to the aeronautical structure.

4. Aeronautical glazing according to claim 2, characterized in that the frame comprises three plies, the thinnest being the structural ply closest to the frame element configured to be fixed to the aeronautical structure.

5. Aeronautical glazing according to claim 1, characterized in that the frame comprises three plies of identical thicknesses.

6. Aeronautical glazing according to one of claims 1 to 5, characterized in that the plies are made of glass, preferably thermally toughened or particularly preferably chemically reinforced, preferably one of a soda-lime mineral glass or a mineral, borosilicate or aluminosilicate glass.

7. Aeronautical glazing according to one of claims 1 to 6, characterized in that the external retainer is fixed to the aeronautical structure.

8. Aeronautical glazing according to one of claims 1 to 6, characterized in that the internal retainer is fixed to the aeronautical structure.

9. Aeronautical glazing according to one of claims 1 to 8, characterized in that it comprises a first seal (116a; 216a; 316a; 416a; 516a; 616a) between the external retainer, respectively the external counter-retainer, and the external fold, one branch of which extends peripherally over the insert fixed at the edge of the external surface of the fold. outermost structural ply and, where appropriate, a second seal (116b; 216b; 316b) between the internal retainer, respectively the internal counter-retainer, and the inner edge of the innermost structural ply and of the insert fixed thereto.

10. Aeronautical glazing according to one of claims 1 to 6 and 8, characterized in that it comprises a thickness shim (417; 517; 617) between the internal retainer and the insert fixed at the edge of the internal surface of the innermost structural ply.

11. Aeronautical glazing according to one of claims 1 to 10, characterized in that the at least one fixing element is a bolt.

12. Aircraft equipped with at least one aeronautical glazing according to one of claims 1 to 11.

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