Abstract:
An aircraft windshield that improves pilot and co-pilot&#39;s perception of the outside world. The windshield includes a transparent panel held inside a structure of the aircraft, in which the upper part and the lower part are bridged so that the loads applied to the panel are (at least partially) diverted. Due to part of the loads applied on the panel being diverted, it is possible to provide a larger window panel than currently available that offers better visibility to the outside.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the French patent application No. 1562377 filed on Dec. 15, 2015, the entire disclosures of which are incorporated herein by way of reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention concerns an aircraft windshield. It applies to every type of aircraft and especially to commercial airplanes. 
         [0003]    Generally speaking, commercial airplanes are outfitted with a windshield having several panes of glass. The windshield of a cockpit has many functions. It allows the pilots to have a visibility of the outside surroundings and thus be able to control the aircraft in flight, as well as on the ground. It maintains a given pressure inside the cockpit during flight, namely, at altitudes where the outer pressure is greatly different from that which is needed inside the aircraft for the persons on board. It protects the pilot and co-pilot against impacts from birds, stones, or other various types of objects. It may thus be subject to substantial degradation requiring a replacement: thus, it is preferable that the glass panes be secured to the structure of the cockpit in a way such that they are easily replaceable. 
         [0004]    The windshield should thus meet various criteria of transparency, resistance to structural loads, to pressure, rigidity and solidity to withstand impacts and degradation while allowing for interchangeability, and this for the service life of the airplane. 
         [0005]    There is described in patent application FR 2998865 a windshield  1  as represented in  FIG. 1  comprising six glasses (only half of them being represented in  FIG. 1 ), two  2 F at the front level, namely, facing respectively the pilot and the co-pilot, two  2 L in the side region and two  2 R in the rear area, again with respect to the pilots and co-pilots. 
         [0006]    As illustrated in the embodiment represented in  FIG. 2  (and as also shown by  FIGS. 2 to 5  of the cited patent), quite often, in schematic and simplified manner, a glass  2  of a windshield  1  of an aircraft cockpit is composed of three superimposed plies  4  of transparent material. The outer ply  6  in contact with the outside atmosphere presents characteristics which allow it to resist abrasion and especially the movement of the windshield wipers, but does not ensure the mechanical strength of the windshield. That strength is provided by the other two plies  7 ,  8 . 
         [0007]    The extremity of the three plies  4  is encircled by a one-piece gasket  10 . 
         [0008]    The gasket  10  and one or more of the extremities of the three plies  4  are enclosed between a one-piece flange  12  and the structure  14  of the cockpit of the aircraft and more particularly a frame provided for this purpose. The flange  12  is secured to the frame with the aid of an assembly system of the nut/screw  16  or equivalent type. 
         [0009]      FIG. 2  shows the bonding between the two front glasses  2 F and  2 F′ (not represented in  FIG. 1 ) of the windshield. The framing of the glass  2 F is adjacent to the framing of the glass  2 F′ so as to form an angle allowing the two respective glasses no longer to be located in the same plane, but instead be oriented to face the pilot and the co-pilot, respectively. The framing of the glasses  2 F in opaque material forms a nontransparent band  17  between the two glasses  2 F and  2 F′. As a result, the bond between the two front glasses disturbs the visual access of the pilot and co-pilot to the outer surroundings. 
         [0010]    In fact, all the bonds between the glasses  2 , namely, between the rear glass  2 R and the side glass  2 L, between the side glass  2 L and the front glass  2 F and between the front glasses  2 F,  2 F′ not only diminish the visibility of the pilots and co-pilots in the outer space, but also provides an impediment to their piloting which increases with the size of the space separating the glasses. 
       SUMMARY OF THE INVENTION 
       [0011]    Thus, the purpose of the present invention is to mitigate this drawback and to propose a windshield which is able to improve the perception of the outer world by the pilot and co-pilot. 
         [0012]    The aircraft windshield includes a transparent panel held inside a structure of the aircraft, in which the upper part and the lower part are bridged by an elongated structural element so that the loads applied to said panel from the upper and lower part are at least partially diverted. 
         [0013]    Due to part of the loads applied on the panel being diverted, it is possible to design a larger window panel that offers better visibility to the outside. 
         [0014]    The windshield has at least one of the following optional characteristics, taken alone or in combination. 
         [0015]    The structural element is independent of the panel, at a distance from the panel, and positioned transversely between the lateral parts of the structure framing the panel, at a distance from them. 
         [0016]    The panel is continuous with regard to the structural element. 
         [0017]    The panel has a curvature at least in one transverse direction. 
         [0018]    The bridge comprises an elongated structural element, one of whose ends is attached to the upper part of the aircraft structure and the other end is attached to the lower part. 
         [0019]    The structure of the aircraft framing the panel is of greater thickness than the thickness of the panel so as to form a recess. 
         [0020]    The structural element is a rod hinged about a pivot at each of its ends to the aircraft structure framing the panel. 
         [0021]    The bridged panel is the front panel and the bridge is realized by a central rod positioned in a vertical plane P of symmetry of the aircraft. 
         [0022]    The bridge is present in the form of a structural element of quadrangular cross section. 
         [0023]    The bridge is present in the form of a structural element having two coaxial parts fitted one into the other. 
         [0024]    The windshield comprises a plurality of bridged panels. 
         [0025]    A panel of the windshield comprises a plurality of bridges. 
         [0026]    According to one particular form, the windshield comprises a single panel provided with a plurality of bridges. 
         [0027]    The present invention also concerns the aircraft provided with a windshield having the above characteristics. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    Other purposes, advantages and characteristics of the invention will appear upon perusal of the following description of the windshield according to the invention, given as a nonlimiting example with reference to the enclosed drawings, in which: 
           [0029]      FIG. 1  is a partial perspective view of a windshield according to the prior art; 
           [0030]      FIG. 2  shows a schematic and partial simplified view in cross section along a horizontal plane of the bond between the two front glasses of a windshield of known type; 
           [0031]      FIG. 3 a    shows a schematic partial simplified view in plan view of a front tip of an aircraft according to the present invention from the side; 
           [0032]      FIG. 3 b    shows a schematic partial simplified view in plan view of an enlarged front view of the windshield of said front tip; 
           [0033]      FIG. 4  is a partial sectional view of the windshield along a central vertical plane of symmetry of the support rod of the windshield; 
           [0034]      FIG. 5  is a partial sectional view of another embodiment of the windshield along a central vertical plane of symmetry of the support rod of the windshield; 
           [0035]      FIG. 6 a    shows a partial schematic view of the cockpit in section along a horizontal plane located in the area facing the pilot and co-pilot according to the prior art; 
           [0036]      FIG. 6 b    shows a partial schematic view of the cockpit in section along a horizontal plane located in the area facing the pilot and co-pilot according to the present invention; 
           [0037]      FIG. 7  shows a partial schematic view of the cockpit in section along a horizontal plane located in the area facing the pilot and co-pilot according to one embodiment of the rod according to the present invention; 
           [0038]      FIG. 8  shows a cross section of another embodiment of the rod; 
           [0039]      FIGS. 9 a  to 9 e    show a schematic front plan view of the windshield according to different embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0040]    As shown in  FIGS. 3 a  and 3 b   , an aircraft  18  has a windshield  20  comprising a single transparent front panel  22  facing the pilot and co-pilot, two side panels  24   a,    24   b  and two rear panels  26   a,    26   b.  The transparent panels used in the windshields are for the most part still comprised today of laminated glass: these are known as glass panels or glasses, due to the fact that they contain glass. However, in certain touring airplanes one can now find panels of polymethylmethacrylate more commonly known as Plexiglas. One may also find writings about windshields of acrylic or polycarbonate. For this reason, in the rest of the description the term panel will be used to designate more generally the glasses of a windshield taking into account modern developments of the materials used. 
         [0041]    The presence of the side panels  24   a,    24   b  and/or rear panels  26   a,    26   b  depends on the size of the aircraft and more particularly its cockpit  28 . 
         [0042]    The panels  22 ,  24  and  26  are curved at least in one direction transversally to said panel (direction perpendicular to its longitudinal direction). In the embodiment illustrated, the panels have a double curvature, transversal and longitudinal. The curved shape of the panel  22  allows it to adapt perfectly to the double curvature of the front tip, thus reducing the aerodynamic drag of the aircraft  18 . 
         [0043]    In all of the figures, it is assumed that the airplane is resting on a horizontal ground, from which a vertical direction is a direction perpendicular to the ground and likewise perpendicular to the longitudinal direction of the aircraft. The vertical direction and the longitudinal direction form a vertical plane parallel to a plane of symmetry of the aircraft. 
         [0044]    The front panel  22  comprises an upper edge  30 , a lower edge  32  and two lateral edges  34 ,  36 . The aircraft  18  has a central vertical overall plane of symmetry P (represented in  FIG. 3 b   ). The plane of symmetry P divides the cockpit  28  into two parts: in one of them is situated the pilot and in the other the co-pilot. The front panel  22  is symmetrical with respect to the plane P. The lateral panels  24   a,    24   b  and the rear panels  26   a,    26   b  are symmetrical with respect to the plane P. 
         [0045]    As shown by  FIG. 4 , the front panel  22  is mounted on a structure  38  of the aircraft by means of a fixation system  40 , explained further below. 
         [0046]    The front panel  22  comprises three plies, an outer ply  42 , a middle ply  44  and an internal ply  46 . The ends of the plies are surrounded by a sealing gasket  48 . The peripheral edge  30 ,  32 ,  34 ,  36  of the panel  22  and more precisely in the embodiment illustrated, the sealing gasket  48 , is sandwiched between the structure  38  of the airplane and a fixation flange  50 . The structure of the aircraft  38  and the fixation flange  50  respectively form directly or indirectly a clamp in which the panel  22  is held by its peripheral edges  30 ,  32 ,  34 ,  36 . The structure  38  of the airplane and the fixation flange  50  are clamped with the aid of a nut and screw type assembly system  52 . 
         [0047]    In the embodiment illustrated, the outer ply  42  has a smaller dimension in the two directions, longitudinal and lateral, of the panel than the other two plies  44 ,  46 . The dimension of the outer ply  42  is such that the ply surrounded by the gasket  48  interlocks in the opening provided by the fixation flange  50 . The outer surface  54  of the outer ply  42  is nearly, except for the height of the gasket, continuous with the outer surface  56  of the fixation flange  50 . The middle  44  and inner  46  plies extend beyond the outer ply  42  toward the structure  38  of the aircraft: the ends of the middle  44  and inner  46  plies are squeezed between the flange  50  and the structure  38  of the aircraft. The outer ply  42  held against the other two plies by the gasket  48  is inserted and adjoins the free end of the flange  50 . 
         [0048]    The structure  38  of the airplane is present in the form of a hollow box  58  of more or less complex shape. The box  58  comprises an outer  60  whose outer surface  62  is continuous with the outer surface  56  of the flange  54  and the outer surface  54  of the outer ply  42 . The box  58  likewise comprises a lower face  64  joined directly or indirectly by lateral faces  66  to the outer face  60 . The box  58  surrounds the panel  22  and thus comprises four parts, an upper part, a lower part, and two lateral parts. Only the upper  68  and lower  70  parts of the box are represented in  FIG. 4 . The structure of the aircraft in the region where the panel is secured and in the embodiment shown the box has a greater thickness than that of the panel  22  so as to form a recess  71 . 
         [0049]    The front panel  22  must withstand the pressure loads of the cockpit. Now, the dimensions of the front panel  22  are increased as compared to the front glasses of known type. The windshield  20  comprises a bridge between the upper part and the lower part of the structure  38  of the aircraft framing the panel  22 , or the box  58  here, able to absorb a portion of the loads applied to the panel  22 . The bridge means here the putting in place of a structural element able to divert at least in part the pressure loads which are applied from the upper part  68  of the box above the panel  22  onto the panel  22  and onto the lower part  70  of the box below the panel  22 . The structural element takes up at least some of the forces applied to the panel. The term bridge is likewise used because the rod links the upper and lower parts of the box on the inside or the recess side  70 , thus forming a bridge between them, a load absorbing bond. 
         [0050]    The structural element is distinct and independent from the panel  22 : it is not connected in any way to the panel. The structural element is connected to the panel holding structure but not at all to the panel proper. It is not part of the panel holding structure. 
         [0051]    The structural element is located at a distance from the panel  22 , facing the latter, between the lateral parts of the structure framing the panel  22  and at a distance from them. The structural element is not situated opposite the structure framing the panel. In the embodiment illustrated, as will be seen further below, in the case of a single structural element this may be located at equal distance from the lateral parts. The transparent panel presents a continuity in regard to the structural element. The structural element takes up a portion of the forces being exerted on the panel. 
         [0052]    The structural element is of elongated shape, namely, extending in length or also extending more longitudinally than transversally. 
         [0053]    Thus, thanks to the bridge, with the same height and the same thickness of panel as those of the front windshield glasses of known type, the deformation of the panel  22  under the pressure loads of the cockpit remains on the same level. 
         [0054]    The structural element can have any desired form, for example, the form of a rod, beam, brace, support bar or stem. 
         [0055]    In the embodiment illustrated in  FIG. 4 , the structural element is present in the form of a rod  72  secured at one of its ends  74  to the upper part  68  of the box and at the other end  76  to the lower part  70  of the box. The ends  74 ,  76  of the rod are secured by means of a plate  78 ,  80  respectively to the upper part  68  and to the lower part  70  of the box. Each of the ends  74 ,  76  is hinged respectively to the plate  78 ,  80  so as to allow a pivoting link between the rod and the structure of the aircraft or a movement in rotation about an axis  82 ,  84  perpendicular to the axis of the rod  72  and parallel respectively to the associated upper  68  and lower  70  parts of the box. The enabled movement in rotation allows the rod to follow the possible movements of one part of the box in relation to another, while preventing any twisting, buckling, or other possible deformation of the rod. The hinging is done with the aid of any means of known type. In the case of the rod, the rod end in the shape of a bushing rotates about the axis  82 ,  84  provided in the area of the associated plate  78 ,  80 . 
         [0056]      FIG. 5  shows another possible embodiment of the rod  72  in which the rod is no longer hinged but rather secured without hinging at each of its ends by one of its ends  74  to the upper part  68  of the box and at the other end  76  to the lower part  70  of the box. The rod is secured by any known means, for example, by rigid fitting. Only one of its ends need not be hinged, the other one being hinged as described previously. 
         [0057]      FIG. 6 b    shows the effect of the rod  72  on the field of vision of the pilot and co-pilot as compared to  FIG. 66 a    showing the effect of the rigid fitting  17  between two front glasses. The pilot&#39;s head is represented by a circle  88  and that of the co-pilot by a circle  90  in both figures. The field of vision of each of them when their gaze is turned toward the rigid fitting or toward the rod is represented by the space  96  between two dotted lines  92 ,  94 . The hatched space between the two dotted lines  92 ,  94  represents the space of the field of vision of the pilot or co-pilot, respectively, which is blocked by the rigid fitting  17  and the rod  72 . 
         [0058]    The rod  72  being of much smaller size than that of the rigid fitting  17 , it does not impede the central field of vision of the pilot and co-pilot, as shown by  FIG. 6 b   . Hence, the amplitude A of the front field of vision of the pilot and co-pilot represented by the double arrow in  FIG. 6 b    is much more sizeable, nearly double that of windshields of known type in the form illustrated. 
         [0059]    The body  86  of the rod  72  has an optimized shape so that the binocular field of vision of the pilot and co-pilot to the outside can be the best possible. For example, the rod has a quadrangular section and in the embodiment represented in  FIG. 7 , a diamond shape.  FIG. 8  shows another possible form of rod with an oval section. The rod in this configuration comprises two coaxial cylindrical parts fitted one inside the other. This profile makes it possible to achieve a double path for the flow of forces. 
         [0060]      FIGS. 9 a  to 9 e    show that the present invention can be applied to panels other than the central panel.  FIG. 9 a    includes the windshield of the prior art in order to make possible a comparison of each of the possible applications illustrated in  FIGS. 9 b    to  9   e.    
         [0061]      FIG. 9 b    shows the embodiment described above in which the front panels have been merged into a single front panel  22 . 
         [0062]      FIG. 9 c    shows that the present invention also applies to the side panels  24   a,    24   b  and rear panels  26   a,    26   b.  The side  24   a  and rear  26   a  panels are joined into a single panel. The same is true of the side  24   b  and rear  26   b  panels. The front panel remains a two-piece panel. A rod is introduced for each resulting “rear-side” panel. The rod is represented by a dotted line to show one possible position thereof in the illustrated embodiment. It is then the side and rear field of vision of the pilot and co-pilot which is improved. 
         [0063]      FIG. 9 d    shows a merging of the rear panel  26   a  with the side panel  24   a , itself merged with the front panel  22   a.  The same is true of the rear panel  26   b,  the side panel  24   b  and the front panel  22   b.  In this case shown, the front panel remains in two pieces. It is then necessary to introduce four rods, two on each side. In the same way as for  FIG. 9 c   , each rod is represented by a dotted line. The side and rear field of vision is then further improved as compared to the previous configuration illustrated in  FIG. 9   c.    
         [0064]      FIG. 9 e    shows the merging of all the panels with each other to form a single windshield. Five rods are required. The previous four rods and the central rod of the embodiment as described in detail previously. 
         [0065]    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.