Aircraft canopy having a window pane with an integrated flange and load-transferring and distributing members

Abstract

An aircraft canopy includes a window pane, a frame from a primary structure of the aircraft, and a flange fastened to the frame with fastening screw, characterized in that: the flange is secured to the peripheral edge of the window pane by engaging of at least one plate of the flange between plies of the window pane, so that flange and window pane form an all in one-piece assembly, at each fastening screw, a load-transferring and distributing member is arranged between an outer surface of the flange and the fasting screw, a cavity being provided in the flange for receiving the load-transferring and distributing member, the member having a recess for receiving the screw head.

Claims

1. An aircraft canopy comprising: a laminated window pane, comprising a superposition of plies and having a peripheral edge; a frame belonging to a primary structure of the aircraft; a flange fastened to the frame by fastening screws having screw heads retracted into the thickness of the flange, the flange fastened to the peripheral edge of the window pane; and at each fastening screw, a load-transferring and distributing member inserted between an outer surface of the flange and said fastening screw, a cavity arranged in the flange to accommodate the load-transferring and distributing member, a hole provided at the bottom of the cavity for passing a screw shank of the fastening screw, the load-transferring and distributing member having a recess for accommodating the screw head and a drilled hole for passing the screw shank, wherein the flange comprises a superposition of plates including an outer plate covering the peripheral edge of the laminated window pane and an inner plate forming an inner surface of the flange, at least part of the inner plate bearing against a web of the frame, wherein at least one of the plates of the flange, qualified as anchoring plate, is embedded between two plies of the window pane along the peripheral edge of the window pane, and wherein at least one cavity is delimited by a peripheral wall comprising, from the inside to the outside of the aircraft: the wall of the hole made in the inner plate of the flange for passing the screw shank, the load-transferring and distributing member having a cylindrical tubular lower portion inserted in the hole so as to rest on the frame, and a stepped portion formed by sections of the plates of the flange, the load-transferring and distributing member having an outer lateral side with successive projections that is complementary to the stepped portion of the peripheral wall of the cavity.

2. The aircraft canopy according to claim 1, wherein the cavity and the member sink into the thickness of the flange at least down to the anchoring plate.

3. The aircraft canopy according to claim 1, wherein the fastening screws are hexagon-head screws and wherein the recess of the load-transferring and distributing members has a bottom with a flat surface.

4. The aircraft canopy according to claim 1, wherein the anchoring plate is an intermediate plate between the outer plate and the inner plate.

5. The aircraft canopy according to claim 1, wherein the anchoring plate penetrates the laminated window pane over an anchoring depth equal to at least 10 mm.

6. The aircraft canopy according to claim 1, wherein each cavity has a width decreasing from the outside of the aircraft.

7. The aircraft canopy according to claim 1, wherein at least one cavity is delimited by a peripheral wall formed by sections of the plates of the flange.

8. The aircraft canopy according to claim 1, wherein at least one of the cavities is delimited by a peripheral wall formed by sections of the plates of the flange and comprises, from the outside to the inside of the aircraft: an upper projection at the junction between the outer plate and the plate adjacent to the outer plate of the flange, projection on which an upper outer collar of the load-transferring and distributing member comes to bear; a truncated portion; a lower projection at the junction between the anchoring plate and the plate situated above the anchoring plate, the wall of the hole made for passing the screw shank, the load-transferring and distributing member having a cylindrical tubular lower portion inserted in the hole so as to rest on the frame.

9. The aircraft canopy according to claim 1, wherein at least one of the cavities is delimited by a peripheral wall formed by an outer side of the outer plate of the flange, said outer plate turning down into the cavity towards the inside of the aircraft.

10. The aircraft canopy according to claim 1, further comprising: for each fastening screw, a dry O ring seal between an inner side of the flange and the frame, said dry O ring seal surrounding a tubular lower portion of the member accommodating the screw shank, a dry peripheral seal, interposed between a peripheral lateral side of the flange and a flank of the frame, a dry peripheral seal, interposed between the outer plate of the flange and an outer front side of the laminated window pane, and a dry peripheral seal, interposed between the anchoring plate of the flange and a ply of the window pane that is contiguous with the anchoring plate.

11. The aircraft canopy according to claim 1, further comprising, for each fastening screw, a plug configured to close the recess accommodating the screw head, and to be fastened to the corresponding load-transferring and distributing member by interlocking.

12. The aircraft canopy according to claim 1, wherein the window pane integrates an electric circuit powered by a connector connected to the window pane by an electric cable emerging from the window pane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other details and advantages of the present invention will emerge on reading the following description, which refers to the attached schematic drawings and refers to preferred embodiments, provided as non-limitative examples. On these drawings:

(2) FIG. 1 is an exploded schematic view, in perspective, of a canopy window pane of the prior art for assembly from outside,

(3) FIG. 2 is an exploded schematic view, sectional, of a canopy according to an embodiment of the invention,

(4) FIG. 3 is a schematic view, sectional, of a canopy according to an embodiment of the invention, showing a first embodiment of the load-transferring and distributing member proposed by the invention,

(5) FIG. 4 is a schematic view, sectional, of a canopy according to an embodiment of the invention, showing a second embodiment of the load-transferring and distributing member proposed by the invention,

(6) FIG. 5 is a schematic view, sectional, of a canopy according to an embodiment of the invention, showing a third embodiment of the load-transferring and distributing member proposed by the invention.

DETAILED DESCRIPTION

(7) In the detailed description that follows, the terms “upper”, “lower”, “horizontal” or “vertical” are used with reference to a vertical direction given by the height of the drawing board in question and not with reference to terrestrial gravity, the illustrated devices not necessarily being shown in a position that corresponds to their installation position on the aircraft.

(8) Thus for example, in FIGS. 3 to 5, which are sections along planes containing the axis of a screw for fastening the canopy in which the axis of the screw is shown vertically on the figure, a plane qualified as horizontal on these figures is a plane orthogonal to the axis of the fastening screw and consequently substantially parallel to the plane of the canopy window pane.

(9) A canopy according to an embodiment of the invention comprises (see in particular FIGS. 1 and 2) a window pane 2 with integrated flange 6, intended to be assembled on a frame 4 of the primary structure of an aircraft. Contrary to known prior canopies, in a canopy according to an embodiment of the invention, the window pane 2 and the flange 6 are pre-assembled.

(10) A canopy according to an embodiment of the invention comprises a window pane 2 with integrated flange 6 intended to be assembled on a frame 4 of the primary structure of an aircraft. Contrary to known prior canopies, in a canopy according to an embodiment of the invention, the window pane 2 and the flange 6 are pre-assembled (see FIG. 2). The frame 4, however, can be similar to a known frame.

(11) The flange 6 according to an embodiment of the invention is a laminated flange. This means that the flange 6 comprises a superposition of metal plates, numbering five in the illustrated non-limitative examples. More precisely, the flange 6 includes an outer plate 61 that forms the outer side 66 of the flange, oriented towards the outside of the aircraft, three intermediate plates 62, 63 and 64, and an inner plate 65 forming the inner side 67 of the flange, oriented towards the inside of the aircraft, and at least part of which bears against the frame 4.

(12) Similarly, the window pane 2 is a laminated window pane, which means that it comprises a superposition of layers alternating plies of glass (or other transparent material, for example, an acrylic) and interposed layers of a transparent sealing material. More precisely here, the window pane 2 successively comprises (from the outside towards the inside of the aircraft): a thin outer ply 21, forming the outer side 26 of the window pane (side oriented towards the outside of the aircraft), an interpose 22 of a greater thickness in which an electric circuit 30 is sunk, a thick median ply 23, an interpose 24 of a lesser thickness and a thick inner ply 25 forming the inner side 27 of the window pane (side oriented towards the inside of the aircraft). The median ply 23 and inner ply 25 are structural plies, which confer on the window pane its bending strength. At its peripheral edge 29, the window pane additionally comprises a block 28.

(13) The frame 4 comprises:

(14) an upright 43 that extends in a plane substantially orthogonal to the plane of the window pane 2,

(15) a web 41 that extends in a plane substantially parallel to the plane of the window pane 2 and is extended by a flank 44 extending substantially orthogonally to the plane of the window pane towards the outside,

(16) an inner ledge or heel 42 extending substantially parallel to the plane of the window pane 2 from the upright 43.

(17) The flange 6 is fastened to the window pane 2 by interlocking of the metal plates of the flange in the lamination of the window pane and conversely. In other words, the glass plies of the window pane and the metal plates of the flange are superposed such that, on one hand, the outer plate 61 of the flange extends over the outer ply 21 of the window pane all along the peripheral edge 29 of the window pane, and on the other, at least one metal plate 64 of the flange, called anchoring plate, is interposed between two glass plies of the window pane, here the plies 21 and 23, penetrating in an interposed layer 22.

(18) In the case of a window pane such as that illustrated, which is conventional in that it comprises an inner structural ply (the ply 25), a median structural ply 23 and a thinner outer ply 21, it is preferable for the anchoring plate according to an embodiment of the invention to be inserted in the window pane at the interpose 22 between the thin outer ply and the median structural ply, so that the ply of the window pane bearing most of the forces under the effect of the pressure difference between the pressurized cockpit and the outside of the aircraft is the median structural ply 23. In the illustrated configuration, the anchoring plate is consequently the intermediate plate 64. It could be another intermediate plate with the exception of the intermediate plate adjacent to the outer plate. It could also be the inner plate 65, but the consequence of this would be that the thickness of the interpose 22 would have to be increased, which is of no value and is therefore undesirable (this increase in thickness resulting in an unnecessary increase in the weight of the window pane).

(19) In order to guarantee correct fastening of the flange to the window pane, the anchoring plate penetrates the laminated window pane over an anchoring depth (width of the plate strip sunk in the interposed layer and enclosed between the two glass plies), for example of the order of 15 mm, and preferably equal to at least 10 mm. In practice, this anchoring depth depends on the quality of the adhesion of the interpose 22 to the anchoring plate 64.

(20) The inner side 67 of the flange is pressed against the web 41 of the frame. As indicated previously, the peripheral edge 29 of the window pane 2 is equipped with a block 28 that makes it possible to rectify the thickness of the window pane so that its peripheral edge rests on the heel 42 of the frame when the flange supported by the window pane rests on the web 41 of the frame. This block 28 makes it possible to use window panes of different thickness from different suppliers while keeping an identical aircraft interface, that is to say, a frame having fixed given dimensions. In effect, the window panes offered by the different suppliers are of variable thickness according to the material used to manufacture them. If a very thick window pane is used, this block 28 can disappear.

(21) The flange 6 is fastened to the frame 4 by means of a plurality of hexagon-head screws 8. To do this, a cavity 68, delimited by a peripheral wall 69, is provided in the flange 6 at each fastening screw 8.

(22) According to an embodiment of the invention, a load-transferring and distributing member 10 is interposed between the fastening screw 8 and the flange 6 inside the cavity 68. Exceptionally, and for the sake of clarity, the sectional parts in FIGS. 2 to 5 are not hatched with the exception of the member 10.

(23) The load-transferring and distributing member 10 comprises a recess 101 for accommodating the hexagonal screw head of the fastening screw 8. At the bottom of the recess 101, a drilled hole 102 (see FIG. 5, this drilled hole being common to the embodiments of FIGS. 3 to 5) allows the passage of the shank of the fastening screw 8. In the bottom of the recess 101, the contact surface between the screw head and the member is flat. The member 10 furthermore has an outer lateral side that is complementary to the peripheral wall 69 of the cavity 68.

(24) The tightening torque of the fastening screw 8, transmitted to the member at the flat contact surface (of reduced dimension) between the hexagonal screw head and the bottom of the recess 101, is distributed over the outer lateral side of the member (of larger dimension) when it is transmitted to the flange 6. The member 10 therefore makes it possible locally to limit the pressure exerted on the flange by distributing over a larger surface the force received from the fastening screw on one hand and the forces exerted by the window pane on the other under the effect of the pressurization of the cockpit (said forces of pressurization of the cockpit are illustrated by arrows on FIGS. 3 to 5). This distribution makes it possible to avoid compression of the flange 6 at the fastening screws and also to limit the pressure exerted at points on the peripheral edge of the window pane facing each fastening screw.

(25) The cavity 68 and the member 10 can adopt different shapes, including those illustrated on FIGS. 3 to 5. The members 10, 10′ and 10″ illustrated on these three figures have in common in particular that they are rotationally symmetrical and that they include a recess 101 such as that previously described, but they differ in the shape of their outer lateral sides coinciding with the peripheral wall 69, 69′, 69″ of the cavity.

(26) On FIG. 3, it can be observed that the cavity 68 is delimited by a peripheral wall 69 successively formed (from the outside towards the inside of the aircraft), by the chamfered section 70 of the outer plate 61 of the flange, a projection 71 horizontal to the junction between the outer plate 61 and the intermediate plate 62, a truncated portion 72 formed by the oblique sections of the intermediate plates 62 and 63, a projection 73 horizontal to the junction between the intermediate plates 63 and 64, a cylindrical portion formed by a hole 74 passing through the intermediate plate 64 and the inner plate 65.

(27) In a complementary fashion, the outer lateral side of the member 10 successively has an outer upper collar with chamfered edge, a first flat portion bearing against the projection 71, a truncated portion in contact with the truncated portion 72 of the cavity wall, a second flat portion bearing against the projection 73 of the cavity, a cylindrical portion facing the cylindrical portion 74 of the cavity, and a flat end that rests on the web 41 of the frame 4.

(28) In the variant illustrated on FIG. 4, the peripheral wall 69′ of the cavity has a succession of steps formed by horizontal projections at the junctions between the different metal plates of the flange 6′. An additional projection is formed in the thickness of the inner plate in order to guarantee a distance calibrated by the thickness of the member. This thickness between the hexagonal screw head and the location where the member is in contact with the frame 41 makes it possible not to compress the films of adhesive situated between the plates.

(29) In the variant illustrated on FIG. 5, the cavity has a smooth globally truncated peripheral wall 69″ formed by the outer side of the outer plate 61″ of the flange, said outer plate is turned down towards the inside of the cavity against the sections of the other plates of the flange.

(30) In the three illustrated examples, sealing is ensured by four dry seals such as silicone seals:

(31) a first dry seal 31 that extends “horizontally” between the outer plate 61 (or 61′ or 61″) of the flange and the outer ply 21 of the window pane, said seal also extends “vertically” between the peripheral edge of the outer ply 21 and the flange (or, more precisely, the intermediate plate 62) and between the peripheral edge of the interpose 22 and the flange (or more precisely, the intermediate plate 63); the seal 31 therefore has a straight section in the shape of an angle piece,

(32) a second dry seal 32 that extends “horizontally” between the anchoring plate 64 and the median ply 23 of the window pane from the anchoring end of the anchoring plate 64 to the inner plate 65 of the flange,

(33) a third dry O ring seal 33, surrounding the cylindrical tubular portion of the member and the shank of the fastening screw 8. This dry O ring seal is compressed between the inner plate 65 of the flange and the web 41 of the frame. It is accommodated in a groove arranged in the inner side of the inner plate 65 (this groove could be arranged as a variant on the outer side of the web 41),

(34) a fourth dry seal 34 pinned between the peripheral edge of the flange 6, 6′, 6″ and the flank 44 of the frame; this seal preferably has a lip, for example in its lower part, which is inserted in a slot arranged in the peripheral edge of one of the plates of the flange, here the inner plate 65.

(35) Each member 10, 10′, 10″ has an outer side that extends and is flush with the outer side 66 of the flange so as to limit aerodynamic perturbations that could be due to the presence of the cavity 68 and of the member.

(36) For the same reasons, the recess 101 of each of the members is closed by a plug 12 whose outer side extends at the outer side 66 of the flange. In order to simplify the installation, this plug 12 preferably comprises hooks 121 (see FIG. 2) with elastic deformation that bear against an inner collar 103 of the member (that is to say, a collar extending radically towards the inside of the member). When a plug is put in place by offering it up above the recess and pressing the plug from the outside against the member, the hooks 121 of the plug are elastically pushed by the inner collar 103 towards the center so as to enable their insertion in the recess, then they spread out again to bear against the collar 103 inside the recess when the plug is fully in place.

(37) A small section hole (not illustrated), for example of a diameter of the order of 0.5 mm, is preferably provided in the outer side of the plug 12 to make it possible to balance the pressure between the outside of the aircraft and the recess accommodating the screw head. This hole also has the advantage of simplifying the extraction of the plug by means of a suitable tool when replacing the window frame.

(38) In a conventional manner, the window pane 2 integrates an electric circuit 30 terminated by a connector 36 intended to be plugged into a complementary connector 37 integral with the primary structure of the aircraft. In a known manner, the connector 37 can be connected to a cable 38 emerging from the frame 4, said cable 38 is electrically powered by the primary electrical network of the aircraft. In known canopies, the connector 36 of the electric circuit of the window pane is fastened directly to the inner ply 25 of the window pane. The addition according to an embodiment of the invention of a cable 35 between the window pane and the connector 36 provides the ability to connect and disconnect the connector 36 to/from the connector 37 without having to remove the joint cover 39 inside the cockpit so as to access the connector. This additional characteristic consequently reduces even further the time for replacing a canopy according to the invention.

(39) Furthermore, the disadvantage of a connector bonded to the window pane as in the prior art is that it masks part of the field of vision offered by the window pane. By deporting this connector to the end of a cable of approximately 20 cm for example, the gain is not only in ease of access for connection/disconnection, but also in visibility, since, once connected, the connectors can be housed in the space delimited the heel 42 of the frame and the joint cover 39.

(40) The invention extends to any variant accessible to the person skilled in the art, that is to say, any variant included in the framework delimited by the attached claims.

(41) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.