Patent Publication Number: US-2020283119-A1

Title: Aircraft Door Structure

Description:
TECHNICAL FIELD 
     The application relates generally to doors and, more particularly, to aircraft door structures. 
     BACKGROUND 
     For some conventional doors for aircraft, a door latching system consists of a moveable latching mechanism and a fixed catch. The moveable latching mechanism that is actuated by the user is mounted to the door itself, with the mechanism being integrated inside the door structure. The area surrounding the door has the fixed or immoveable catch of the latching system. 
     This traditional design means that the structure of the door has to be hollow to allow cables or rods of the moveable latching mechanism to run from the door handle to the latching locations. These passageways need a certain depth/width to allow proper clearance, and may prevent the use of a more compact or weight-efficient structure for the door. Furthermore, the installation of the moveable latching mechanism is complex because it is typically inserted into the door after it has been constructed through multiple access cut-outs in the door that need to be covered over afterwards to eliminate the risk of foreign object damage (FOD) jamming the mechanism. 
     Furthermore, this conventional design may be more difficult to repair or replace because access to the moveable latching mechanism is restricted through a few small openings in the door. 
     SUMMARY 
     In one aspect, there is provided an aircraft, comprising: a fuselage defining an outer surface and an inner surface, the fuselage having a door frame delimiting a door opening extending through the fuselage and providing access to an interior thereof, the door frame having a latch housing portion defining a latch housing cavity extending along a length of the door frame; a door mounted to the door frame and displaceable between an open position and a closed position, the door having a peripheral portion with an outer wall and an inner wall extending from the outer wall inwardly toward the interior of the fuselage, the outer and inner walls delimiting a cavity of the peripheral portion; and a door latch assembly having a first latch member fixedly mounted to the door, and a door manipulator mounted to one of the door and the fuselage and coupled to a second latch member disposed within the latch housing cavity of the door frame, the door manipulator configured to be manipulated to displace the second latch member to engage and disengage the first latch member. 
     There is provided a door structure, comprising: a door frame delimiting a door opening, the door frame having a latch housing portion defining a latch housing cavity extending along a length of the door frame; a door mounted to the door frame and displaceable between an open position and a closed position, the door having a peripheral portion with an outer wall and an inner wall delimiting a cavity of the peripheral portion; and a door latch assembly having a first latch member fixedly mounted to the door, and a door manipulator mounted to one of the door and the fuselage and coupled to a second latch member within the latch housing cavity of the door frame, the door manipulator configured to be manipulated to displace the second latch member to engage and disengage the first latch member. 
     There is provided a method of assembling a door structure, the method comprising: providing a door frame delimiting a door opening and having a latch housing portion defining a latch housing cavity; mounting a door to the door frame, the door having a peripheral portion with an internal cavity; fixedly mounting a first latch member to the door; and displaceably mounting a second latch member within the latch housing cavity of the door frame, the second latch member being displaceable to engage and disengage the first latch member. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the accompanying figures in which: 
         FIG. 1  is a schematic side view of a rotorcraft in accordance with an embodiment of the present disclosure; 
         FIG. 2A  is a schematic side view of a door structure of the rotorcraft shown in  FIG. 1 ; and 
         FIG. 2B  is a cross-sectional view of part of the door structure of  FIG. 2A , taken along the line IIB-IIB in  FIG. 2A . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an aircraft. The aircraft shown in  FIG. 1A  is a rotorcraft  100 , according to one example embodiment of the aircraft disclosed herein. The rotorcraft  100  features a rotor system  110 , blades  120 , a fuselage  130  defining a cabin  180 , a landing gear  140 , and an empennage  150 . The rotor system  110  rotates the blades  120 . The rotor system  110  includes a control system for selectively controlling the pitch of each blade  120  in order to selectively control direction, thrust, and lift of the rotorcraft  100 . The fuselage  130  represents the body of the rotorcraft  100  and is coupled to rotor system  110  such that the rotor system  110  and the blades  120  may move the fuselage  130  through the air. The landing gear  140  supports the rotorcraft  100  when the rotorcraft  100  is landing and/or when the rotorcraft  100  is at rest on the ground. The empennage  150  represents the tail section of the aircraft and features components of a rotor system  110 ′ and blades  120 ′. The blades  120 ′ may provide thrust in the same direction as the rotation of blades  120  so as to counter the torque effect created by the rotor system  110  and the blades  120 . The fuselage  130  defines an outer surface  132  and an inner surface  134 . The outer surface  132  is exposed and visible, and forms the outer surface of the body of the rotorcraft  100 . The inner surface  134  faces toward the interior of the rotorcraft  100 . 
     The fuselage  130  has multiple door structures  10  or door assemblies. Each door structure  10  includes a door frame  12  (see  FIG. 2A ) and a door  10 A. The door frame  12  forms the structure to which the door  10 A is mounted or fitted. The door frame  12  is the structure which surrounds some or all of the door  10 A. In the depicted embodiment, the door frame  12  is a component of, or integral with, the fuselage  130 . The door frame  12  delimits a door opening  136  or doorway which extends through the fuselage  130  between the inner and outer surfaces  132 , 134 . The door openings  136  provide access to the interior of the fuselage  130 , to the interior of the cabin  180  for example. Each door opening  136  is covered by one of the doors  10 A. It will be appreciated that entry into the fuselage  130 , and exit from fuselage  130 , is achieved through the door openings  136  by opening or closing the corresponding doors  10 A. 
     In  FIG. 1 , each door  10 A is a body which has a window or transparency to admit light. The door  10 A is thus a windowed structure. The doors  10 A shown in  FIG. 1  are passenger doors which open and close to allow passengers to enter and exit the cabin  180  of the rotorcraft  100 . Other doors  10 A are within the scope of the present disclosure. For example, in an alternate embodiment, the door  10 A is a cargo door that admits no light therethrough. In another alternate embodiment, the door  10 A is a panel that admits no light therethrough. Therefore, reference to doors  10 A herein does not limit the door  10 A to being only a light-admitting structure. 
     Referring to  FIGS. 2A and 2B , each door  10 A is any suitable moveable part or barrier which is mounted to the door frame  12  about one of the door openings  136  using any suitable structure such as hinges. It will be appreciated that the door  10 A may also slide with respect to the door frame  12 , and thus may have suitable mounting structure to enable such functionality. Each door  10 A is displaceable between an open position to provide access to the interior of the fuselage  130  via the door opening  136 , and a closed position (shown in  FIG. 2A ) to block the door opening  136  and prevent access therethrough. 
     The rotorcraft  100  also has a door latch assembly  30 . The door latch assembly  30  is used to open and close the door  10 A, and to latch and unlatch the door  10 A to the door frame  12 . The door latch assembly  30  thus forms a latching mechanism for the door  10 A. When the door  10 A is latched, it is in a closed position and is maintained in that position by the door latch assembly  30 . When the door  10 A is unlatched, it is in an open position. Locks or a locking mechanism can be used with the door  10 A and/or the door latch assembly  30  to lock and unlock the door  10 A when it is latched. As will be described in greater detail below, some components of the door latch assembly  30  are positioned on or within the door  10 A, and other components of the door latch assembly  30  are positioned on or within the door frame  12 . The door  10 A and door frame  12  have structure, described in greater detail below, some of which may be used to house or position components of the door latch assembly  30 . 
     With respect to the door  10 A, and referring to  FIG. 2A , the door  10 A has a door body  11  with a peripheral portion  13 . The peripheral portion  13  of the door  10 A is a structural segment of the door  10 A that delimits the periphery of the door  10 A. The peripheral portion  13  gives structure to the door  10 A along its periphery to reinforce the strength and stiffness of the door  10 A along its periphery. The door body  11  also has an interior portion  11 A positioned inwardly of the peripheral portion  13  and delimited thereby. The peripheral portion  13  in the depicted embodiment extends along all of the periphery of the door body  11 . In an alternate embodiment, the peripheral portion  13  extends along less than all of the periphery of the door body  11 . The door  10 A has a window element  20  in the depicted embodiment which allows light to be admitted through the door  10 A. The window element  20  is any suitable transparency or other body to achieve this purpose. The window element  20  may have any suitable shape or size, and may be made from any suitable material such as a polymer and glass. In the depicted embodiment, the window element  20  is a single layer of glass. Other configurations for the window element  20  are also possible. The window element  20  covers or occupies a window opening  22  which extends through the interior portion  11 A of the door body  11 . The window element  20  has an outer window surface  24 A which forms the external surface of the window element  20 , and an inner window surface  24 B (see  FIG. 2B ). In the depicted embodiment, some of the peripheral portion  13 A delimits the window opening  22  and the window element  20 . In an alternate embodiment, the door  10 A is free of a transparency or window element. 
       FIG. 2B  shows the peripheral portion  13  and window element  20  in cross-section and according to one embodiment of the present disclosure. The peripheral portion  13  includes an outer wall  14 . The outer wall  14  is the segment of the peripheral portion  13  closest to the outer surface  132  of the fuselage  130 . In the depicted embodiment, the outer wall  14  is an outermost wall of the peripheral portion  13 . The outer wall  14  extends between a first end  14 A, sometimes referred to herein as the “window end  14 A”, and a second end  14 B, sometimes referred to herein as the “fuselage end  14 B”. The second end  14 A is the extremity of the outer wall  14  which is closest to a center of the window opening  22 , and furthest from the fuselage  130 . The fuselage end  14 B is the extremity of the outer wall  14  which is closest to the fuselage  130 , and furthest from the center of the window opening  22 . An inner wall  16  extends from the outer wall  14  inwardly. When the door  10 A in the depicted embodiment is in the closed position, the inner wall  16  extends from the outer wall  14  inwardly toward the interior of the fuselage  130 . The outer and inner walls  14 , 16  meet and are bonded or fastened together. The inner wall  16  has a V-shape in the illustrated cross-section. The inner wall  16  includes a first segment  16 A and a second segment  16 B in the depicted embodiment. The first and second segments  16 A, 16 B of the inner wall  16 , and the outer wall  14 , are interconnected to form a triangular cross-sectional shape of the peripheral portion  13 . The triangular cross-sectional shape of the peripheral portion  13  may or may not be present throughout the entire extent of the peripheral portion  13 . The first segment  16 A of the inner wall  16  extends inwardly from the outer wall  14  at the second end  14 A. The first segment  16 A of the inner wall  16  extends inwardly in a direction toward the fuselage  130  from the outer wall  14  at the second end  14 A. In other embodiments, the inner wall  16  might have a different shape than the triangular shape depicted in  FIG. 2B . 
     In the embodiment shown in  FIG. 2B , the inner wall  16  and the outer wall  14  delimit a cavity  15  of the peripheral portion  13 , such that the peripheral portion  13  is hollow along at least part of its length. Stated differently, the cavity  15  may or may not be present throughout the entire extent of the peripheral portion  13 . The presence of the cavity  15  results in the door  10 A having some depth or thickness at least along the peripheral portion  13 . The cavity  15  in  FIG. 2B  is an internal cavity of the peripheral portion  13  at the cross-section shown, and is closed on all sides by the outer and inner walls  14 , 16 . In some embodiments, some of which are described below, the cavity  15  of the peripheral portion  13  is at least partially filled. 
     For example, and as shown in  FIG. 2B , the cavity  15  is filled or bonded with a stiffener  15 A. The stiffener  15 A is any object or material which increases the stiffness of the peripheral portion  13 , and thus its strength, to reinforce the peripheral portion  13  against out of plane forces. The stiffener  15 A may be made of any suitable material, and have any suitable shape or configuration to achieve such functionality. For example, in the depicted embodiment, the stiffener  15 A has substantially the same cross-sectional shape as the cavity  15  (i.e. triangular). The stiffener  15 A fully occupies the cavity  15 , and abuts against the outer and inner walls  14 , 16  of the peripheral portion  13 . In an alternate embodiment, the stiffener  15 A occupies less than the entirety of the cavity  15 , and/or extends across the cavity  15  between the outer and inner walls  14 , 16 . The stiffener  15 A in the depicted embodiment is made from a composite material. The stiffener  15 A in the depicted embodiment is a composite foam. The foam may have a relatively low density. Thus, in the depicted embodiment, the cavity  15  in the door  10 A is filled with a foam stiffener  15 A abutting against the inner and outer walls  16 , 14  along at least some of the length of the cavity  15 . In  FIG. 2B , the stiffener  15 A is shown in the cavity  15  of the peripheral portion  13  of the door  10 A, and it may also be present in other parts of the door  10 A. 
     The cavity  15  may have other shapes as well. In an alternate embodiment, the cavity  15  has a “C” shape in cross-section. In an alternate embodiment, the cavity  15  is partially open, and defined by the inner and outer walls  16 , 14  forming a “T” shape in cross-section. 
     As mentioned above, the door frame  12  may have structure used to house or position components of the door latch assembly  30 . Referring to  FIG. 2B , the door frame  12  has a latch housing portion  17 . The latch housing portion  17  is a portion of the door frame  12  which houses some or all of components of the door latch assembly  30 . The latch housing portion  17  defines a latch housing cavity  17 A which extends along at least some of the length of the door frame  12 . The one or more components of the door latch assembly  30  are positioned in the latch housing cavity  17 A, and are thus protected by the latch housing portion  17 . The latch housing portion  17  may take any suitable configuration to achieve such functionality. For example, in the depicted embodiment, the latch housing portion  17  includes a cover  17 B or trim panel. The cover  17 B is removably mounted to one of the inner and outer surfaces  134 , 132  of the fuselage  130 . As shown in  FIG. 2B , the cover  17 B is mounted to the inner surface  134  of the fuselage  130 , and projects inwardly from the inner surface  134  toward the cabin  180 . The cover  17 B is a protector or housing that is bolted or attached to the fuselage  130 , and defines the latch housing cavity  17 A between itself and the inner surface  134 . Thus, in the embodiment where the latch housing portion  17  includes the cover  17 B, the removability of the cover  17 B makes the components of the door latch assembly  30  easy to access and install because the cover  17 B is fitted onto aircraft structure as a “bolt-on” instead of a “build-in”. In contrast to some conventional structures, the latch or latch components are not trapped within the structure of the aircraft, or accessible only thorough small cut-outs in the aircraft structure. 
     Other configurations for the latch housing portion  17  are possible. In an alternate embodiment, the latch housing portion  17  forms part of the fuselage  130  and the latch housing cavity  17 A is an internal cavity located within the fuselage  130 . The latch housing portion  17  and the latch housing cavity  17 A have vertical orientations in the depicted embodiment, but may also have a different orientation (e.g. horizontal or inclined to both the horizontal and vertical). 
     Referring to  FIGS. 2A and 2B , the door latch assembly  30  is now described in greater detail. The door latch assembly  30  has a first latch member  32  and a second latch member  34 . The first and second latch members  32 , 34  cooperate with one another to latch the door  10 A in the open or closed position, and to unlatch the door  10 A so that it is free to move relative to the door frame  12 . 
     As shown in  FIG. 2A , the first latch member  32  is fixedly mounted to the door  10 A. By “fixedly mounted”, it is understood that the first latch member  32  does not displace with respect to the door  10 A. The first latch member  32  moves with the door  10 A between the open and closed positions. The first latch member  32  may be mounted to the inner or outer surface of the door  10 A, it may be positioned within the door  10 A or exposed thereon, and may be positioned at any location on the door  10 A such as along an edge thereof. A particular configuration of the first latch member  32  is described below, and the present disclosure also includes other configurations of the first latch member  32 . 
     The second latch member  34  is displaceable. The second latch member  34  is displaceable with respect to the door frame  12  to engage with, and disengage from, the first latch member  32 . The second latch member  34  is disposed in whole or in part within the latch housing cavity  17 A of the door frame  12 , and is thus shielded by the latch housing portion  17 . 
     The second latch member  34  is displaced when a person manipulates a door manipulator  36 . The door manipulator  36  is any object which is manipulated by a user to open and close the door  10 A. The door manipulator  36  is mounted to one or both of the door  10 A and the fuselage  130  (e.g. the door frame  12 ). In  FIG. 2A , a portion of the door manipulator  36  is shown mounted to the door frame  12 , and another portion is shown mounted to the door  10 A, as described in greater detail below. The door manipulator  36  is coupled or mechanically linked to the second latch member  34  such that manipulation of the door manipulator  36  will cause displacement of the second latch member  34 . The door manipulator  36 , and its coupling to the second latch member  34 , may take any suitable form to achieve such functionality. 
     For example, in  FIG. 2A , the door manipulator  36  includes, or is in the form of, a handle  36 A mounted to the fuselage  130  in proximity to, on, or over the door frame  12 . The handle  36 A is installed on the fuselage  130  in an area easily accessible by the occupant. In  FIG. 2A , the second latch member  34  includes a cable or rod  34 A extending along a height of the door frame  12 . The handle  36 A is mechanically linked to the rod  34 A such that rotation of the handle  36 A causes the rod  34 A to linearly displace in a direction parallel to its upright or vertical orientation. The door manipulator  36  also includes a switch  36 B positioned on the door  10 A to be accessible by an occupant. The switch is operatively connected to the handle  36 A in any suitable way, such that the switch  36 B may be pushed or activated by the occupant to latch and unlatch, and/or lock and unlock, the handle  36 A and prevent it from rotating. The switch  36 B in the depicted embodiment is accessible only from outside of the fuselage  130 , but it may also be positioned to be accessible from within the fuselage  130 . In one possible embodiment, the switch  36 B is an electro-mechanical component which is electrically coupled to the handle  36 A. 
     Other configurations for the door manipulator  36  and its coupling to the second latch member  34  are possible. In an alternate embodiment, the door manipulator  36  includes, or is in the form of, a knob which is turned to displace a wire or cable of the second latch member  34 . In another alternate embodiment, the door manipulator  36  includes, or is in the form of, a button which is pushed to displace the second latch member  34 . It will therefore be appreciated that the door manipulator  36 , the manner by which it is manipulated, and/or the manner by which it is coupled to the second latch member  34 , may vary. 
     The manipulation of the door manipulator  36  displaces the second latch member  34  within the latch housing portion  17 . In  FIG. 2A , the displacement of the rod  34 A is an axial movement along the longitudinal axis of the rod  34 A. At least parts of the rod  34 A are displaceable in a direction along a height of the door  10 A. Other types of displacement of the second latch member  34  are possible. The second latch member  34  displaces to engage and disengage the first latch member  32 , so as to latch and unlatch the door  10 A. 
     Therefore, in  FIGS. 2A and 2B , the fixed first latch member  32  is disposed on the door  10 A, and the displaceable second latch member  34  is disposed on the structure of the fuselage  130  surrounding and supporting the door  10 A, which is the door frame  12  in the depicted embodiment. No components of the door latch assembly  30  are positioned within the cavity  15  of the door  10 A. It will thus be appreciated that the moving parts of the door latch assembly  30  are not mounted to or in the door  10 A. This configuration of the first and second latch members  32 , 34  allows for positioning the moveable second latch member  34  on the area surrounding the door  10 A (e.g. the door frame  12 ), which is typically large enough to accommodate the moveable second latch member  34 . This configuration of the first and second latch members  32 , 34  allows for optimization of the stiffness of the door  10 A, to minimize the depth or thickness of the door  10 A thus providing weight savings and increased cabin space, and to increase the size of the window element  20  of the door  10 A to provide improved visibility because the moveable portion of the door latch assembly  30  is not present in the door  10 A. 
     One possible configuration of the first and second latch members  32 , 34  is now described with reference to  FIGS. 2A and 2B . The first latch member  32  includes one or more strikers  32 A which are fixedly mounted to the door  10 A. In  FIG. 2A , the first latch member  32  includes two strikers  32 A—an upper striker  32 A′ fixedly mounted to an upper end of the door  10 A and a lower striker  32 A″ fixedly mounted to a lower end of the door  10 A. Each striker  32 A is any suitable object (e.g. catch, bolt, plate, male portion, etc.) which does not displace with respect to the door  10 A, and which is engaged by the moveable second latch member  34 . The strikers  32 A in  FIG. 2A  are separate from one another, and free of any mechanical link to one another. In an alternate embodiment, the strikers  32 A are horizontally spaced apart for a door  10 A that opens vertically by pivoting about a horizontal axis. 
     Still referring to  FIG. 2A , the rod  34 A of the second latch member  34  is a rigid elongated body extending between an upper end and a lower end. The rod  34 A has one or more latches  38 . In  FIG. 2A , the rod  34 A has two latches  38 —a lower latch  38 ′ at a lower end of the rod  34 A and an upper latch  38 ″ at an upper end of the rod  34 A. The latches  38  in the depicted embodiment are “female” components meant to receive the “male” strikers  32 A. Other configurations for the latches  38  are possible and within the scope of the present disclosure. When the door manipulator  36  is manipulated by the operator, the rod  34 A is displaced so that the lower latch  38 ′ engages or disengages the lower striker  32 A″, and so that the upper latch  38 ″ engages or disengages the upper striker  32 A′. The latches  38  are displaceable between a first position in which the latches  38  are disengaged from the strikers  32 A and the door  10 A is unlatched, and a second position in which the latches  38  are engaged with the strikers  32 A and the door  10 A is latched. 
     Reference is made to U.S. patent application Ser. No. 16/161,921 filed Oct. 16, 2018, the entirety of which is incorporated by reference herein. 
     Referring to  FIGS. 2A and 2B , there is disclosed a method of assembling the door structure  10 . The method includes providing the door frame  12 , and mounting the door  10 A to the door frame  12 . The method also includes fixedly mounting the first latch member  32  to the door  10 A, and displaceably mounting the second latch member  34  within the latch housing cavity  17 A of the door frame  12  so that the second latch member  34  is displaceable to engage and disengage the first latch member  32 . 
     In an embodiment, mounting the door  10 A includes forming the door  10 A prior to mounting it. Forming the door  10 A includes forming the peripheral portion  13  of the door  10 A from a single composite laminate delimiting the internal cavity  15 . The composite laminate is a product made by bonding together two or more layers of composite material. It is therefore possible to make the peripheral portion  13  of the door  10 A, as well as other parts of the door  10 A, from a single composite laminate or part, thereby reducing the number of cures required to form the door  10 A to a single cure. 
     Forming the peripheral portion  13  may also include filling the cavity  15  at least partially with the stiffener  15 A. The composite foam of the stiffener  15 A may be positioned between the layers of the single composite laminate or wrapped by said layers, so that the layers are cured and bonded together around the stiffener  15 A in a single, one-step cure. This contrasts with some conventional techniques for making a door which has the moveable components of the latching system. These techniques may involve assembling separate inner and outer composite skins to form the cavity, and fishing the moveable components of the latching mechanism inside the door after the assembly. Such a technique involves two steps, and also requires that multiple cut-out panels be machined in the door to access the moveable components of the latching mechanism inside the door. By helping to eliminate these steps, the forming steps described above help to make the door  10 A lighter and more cost-effective to manufacture. 
     The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. For example, although described herein as an installed feature of an aircraft, the door structure  10  may be provided as an assembly or grouping of its constituent parts. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.