Abstract:
A locking mechanism for an aircraft door includes a plurality of frame-side fittings and a plurality of door-side fittings. Each frame-side fitting includes a pin with an eccentric rotary cylinder mounted on each pin. Each door-side fitting includes an eccentric rotary latch configured to encompass at least a section of a corresponding rotary cylinder. Also a method of locking a door using the locking mechanism.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. 10 2010 013 715.4, filed Apr. 2, 2010 and U.S. Provisional Patent Application No. 61/320,356, filed Apr. 2, 2010, both of which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     The present invention concerns a locking mechanism for an aircraft door, in particular an aeroplane door and also a method for the locking of an aircraft door of this type. 
     BACKGROUND 
     Doors in aircraft must on the one hand be able to be closed tightly and must be able to accommodate securely all loads that occur, and on the other hand must be quick and easy to open in an emergency. There are essentially two principles in accordance with which, for example, locking mechanisms for aeroplane doors can be designed. 
     A door designed in accordance with the so-called abutment principle has abutment fittings on its lateral edges, which in the closed position of the door abut against corresponding fuselage-side fittings such that a form fit is formed between the door and the fuselage, via which the internal forces acting on the door are transferred to the fuselage structure. A door of this type is e.g. shown in the patent document U.S. Pat. No. 4,720,065 and must be lowered for purposes of closing and raised for purposes of opening, in order to release the abutment fittings for an opening movement that is directed outwards. 
     A door designed in accordance with the so-called toggle principle has on its lateral edges toggles that can rotate; as the door pivots inwards these stand parallel to the pivoting movement and engage in fuselage-side holding fixtures. For purposes of closing the door the toggles are set transverse within the holding fixtures, so that here too a form fit is achieved. 
     However, what is disadvantageous for both principles is the high level of complexity of the kinematic system required, since a large number of shafts, bearings, levers, linkages, crank drives and similar are necessary. 
     Moreover, there are aeroplane doors that are designed in accordance with both the abutment principle and the toggle principle. The combination of the two principles leads, however, less to a reduction of complexity than to an increase of the same, and thus, in addition to an increase in weight, to relatively high manufacturing costs. 
     SUMMARY 
     An aspect of the present invention is to provide a locking mechanism for an aircraft door, in particular an aeroplane door, which removes the above-cited disadvantages and with a reduced level of complexity enables a secure locking procedure as well as an opening procedure for emergency situations, and also a method for the locking of an aircraft door. 
     In an embodiment, the present invention provides a locking mechanism for an aircraft door including a plurality of frame-side fittings and a plurality of door-side fittings. Each frame-side fitting includes a pin with an eccentric rotary cylinder mounted on each pin. Each door-side fitting includes an eccentric rotary latch configured to encompass at least a section of a corresponding rotary cylinder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention are described in more detail with reference to schematic representations shown in the drawings, in which: 
         FIG. 1  shows a perspective internal view of an aeroplane door with a locking mechanism in accordance with an embodiment of the invention, 
         FIGS. 2 and 3  show a rotary cylinder of the locking mechanism from  FIG. 1 , 
         FIGS. 4 and 5  show a rotary latch of the locking mechanism from  FIG. 1 , 
         FIGS. 6 and 7  show sketches to illustrate an eccentricity of the rotary cylinders and the rotary latches in accordance with an embodiment of the invention, and 
         FIGS. 8 to 10  show steps in the method for the locking of the aeroplane door in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A locking mechanism of an aircraft door in accordance with an embodiment of the invention has a multiplicity of frame-side and door-side fittings. The frame-side fitting have pins, on which an eccentric rotary cylinder is mounted in each case. In accordance with the invention the door-side fittings are designed as eccentric rotary latches for purposes of encompassing sections of the rotary cylinders. The locking mechanism in accordance with the invention is distinguished in particular by a kinematic system that is reduced in its complexity, and thus simplified, since no movement of the door in the vertical direction is necessary for opening or closing purposes. By this means a multiplicity of levers, shafts and other mechanical actuation elements can be dispensed with, as a result of which the locking mechanism is moreover optimized in terms of weight. The lack of a rise or fall movement in the vertical direction makes possible a smaller fuselage-side door aperture compared with conventional solutions, as a result of which the stability of the fuselage is significantly increased. Moreover, relatively narrow lateral gaps between the door and the door frame are possible. Furthermore, by virtue of the lack of a rise or fall movement of the door a simplified sealing concept is possible. Furthermore, the locking mechanism in accordance with embodiments of the invention enables a quasi-floating mounting of the door in its fuselage-side door frame, so that no twisting of the fuselage is introduced into the door, as a result of which both the door itself, the connection of the door frame to the fuselage, and also the door frame per se, can be embodied in a load-optimized manner. In other words, compared with the previous toggle principle, thrust loads resulting from the door frame displacements that already arise under normal flight conditions into the door structure can be avoided. 
     In one embodiment the rotary latches are in each case designed as radially-extended head sections of a rotary bar, which protrude laterally from the aircraft door. By this means in the particularly heavily loaded upper and lower door regions it is possible to space the individual rotary latches closer together than in a less heavily loaded intermediate region of the door. 
     The locking mechanism can be particularly easily embodied if both the rotary latches and also the rotary cylinders have a uniform design. This makes it possible that for locking or opening purposes all rotary latches can essentially be rotated through the same angle of rotation, which allows the use of a central kinematic system, i.e. a simplified actuation mechanism. Here the locking mechanism can be actuated manually with a hand lever, or can be electrically actuated via servomotors. 
     To ensure that when closing the door the rotary cylinders are located in a defined initial position, it is advantageous if they are pre-loaded by a spring into their initial or neutral position. 
     Opening of the door without any actuation of the locking mechanism can be achieved in that the rotary latches can be retracted into the aircraft door such that the form fit between the rotary cylinders and the rotary latches can be released without any rotation of the rotary latches in the opening direction. 
     In a method in accordance with an embodiment of the invention for the locking of an aircraft door with a locking mechanism of this type the door is initially pivoted into the fuselage-side door frame. The locking mechanism is then actuated such that the rotary latches encompass sections of the rotary cylinders and after rotation of the rotary latches through an angle of rotation, the rotary latches and the rotary cylinders are mutually locked. In this method it is particularly advantageous that the door does not have to be moved in the vertical direction, either for purposes of locking, or for purposes of opening. In accordance with an embodiment of the invention the door is exclusively opened and closed via a pivotal movement about a vertical axis. 
     In one example of embodiment the aircraft door is already securely and reliably locked from an angle of rotation of some 100°. 
     In the figures the same design elements bear the same reference numbers, wherein where there is a plurality of the same design elements just one element can be provided with a reference number in the interests of clarity. 
       FIG. 1  shows an aeroplane door  2 , which is fitted with a locking mechanism  4  for opening, closing and locking purposes. The aeroplane door  2  has an outer skin  6 , an inner skin that is not represented, and also an interior structure  8  arranged between the outer skin  6  and the inner skin for purposes of stabilizing the aeroplane door  2 . The interior structure  8  has two lateral vertical frame elements,  10 ,  12 , which are spaced apart from one another, via in each case an upper and a lower frame element  14 ,  16 , extending in the longitudinal direction of the aeroplane, i.e. horizontally. 
     The locking mechanism  4  has a multiplicity of rotary latches  18 , which protrude from the lateral frame elements,  10 ,  12 , and in each case form a head section of a rotary bar  22  that is guided in a hole  20  of the frame elements,  10 ,  12 . In the interests of clarity the rotary latches  18  are only shown in the right-hand vertical frame element  12  in accordance with the representation  1 . The rotary bars  22  run in the longitudinal direction of the aircraft and can be pivoted through an angle of rotation a by means of a kinematic system or an actuation mechanism  24  that is not described in any further detail. The actuation mechanism  24  can be activated manually or electrically via servomotors. The rotary bars  22  run parallel to one another, wherein in the edge region, i.e. in the region of the horizontal frame elements  14 ,  16 , the rotary bars  22  and thus the rotary latches  18  are spaced closer together than in the intermediate region. 
     On the fuselage-side, or door frame-side, the locking mechanism  4  has a multiplicity of rotary cylinders  26 , sections of which are in each case encompassed by one of the rotary latches  18  during the locking procedure. As shown in  FIGS. 2 and 3 , each of the rotary cylinders  26  is mounted eccentrically on a pin  28 , which via its foot section  30  is securely attached to the door frame  32 . For purposes of transferring the rotary cylinders  26  into their neutral or initial position a rotary spring  34  is arranged in the region of the foot section  30  in each case, which is actively engaged with the rotary cylinder  26 . 
     As shown in  FIG. 4 , the rotary latches  18  are in each case designed as a sickle-shaped claw  36 , which defines an eccentric holding fixture  38  with a peripheral opening  39  for purposes of encompassing a section of the rotary cylinders  26 . As per  FIG. 5 , the rotary latches  18  are essentially designed as radial extensions of the rotary bars  22 . In order to enable an emergency opening of the aeroplane door  2  without an actuation of the locking mechanism  4 , the rotary bars  22  in the region of the radial extensions, i.e. the rotary latches  18 , are guided in the holes  20  of the vertical frame elements,  10 ,  12 . By this means it is possible to retract the rotary latches  18  into the interior structure  8  between the lateral frame elements,  10 ,  12 , and thus to extract them from the rotary cylinders  26  in the longitudinal direction, and thereby release the form fit between the rotary latches  18  and the rotary cylinders  26 . 
     As already stated above, and as can be discerned in particular from  FIGS. 6 and 7 , the holding fixtures  38  of the rotary latches  18 , and also the rotary cylinders  26  are eccentrically embodied, i.e. mounted. During the locking procedure the rotary latches  18  run with their inner periphery  40  onto the outer periphery  42  of the rotary cylinders  26  and drive the latter, wherein the point of rotation  44  of the rotary latches and the point of rotation  46  of the rotary cylinders  26  are in each case arranged relative to one another such that in the locking position shown in  FIG. 7  with a pressure load on the aeroplane door  2 , for example as a result of internal cabin pressure, a moment is introduced via a force F into the locking mechanism  4 , via which the rotary cylinders  26  are always pushed or transferred into the locking position, so that even in the unlikely event that the aeroplane door  2  has not been closed correctly, any inadvertent opening of the aeroplane door  2  is prevented (see forces polygon  48 ). In this manner the aeroplane door  2  has a quasi-automated locking process. 
     In what follows steps of a method in accordance with an embodiment of the invention for the locking of an aeroplane door  2  with the locking mechanism  4  are elucidated with the aid of  FIGS. 8 ,  9  and  10 . The aeroplane door  2  is open and via a pivotal movement about a vertical axis is moved in the horizontal direction in the direction of the door frame  32 . The rotary latches  18  point with their lateral openings  39  in the pivotal direction, and are located in the initial position, in which their angle of rotation α=0°. The rotary cylinders  26  are located in their neutral position that is pre-loaded by a spring. As soon as the aeroplane door  2  is closed, as shown in  FIG. 8 , and the rotary cylinders  26  are accommodated in the holding fixtures  38  of the rotary latches  18 , the rotary latches are rotated via the actuation mechanism such that with their inner periphery  40  they run onto the outer periphery  42  of the rotary cylinders  26 . As a result of the eccentricity of the rotary latches  18  and the rotary cylinders  26 , the rotary latches  18  drive the rotary cylinders  26 , so that these also execute a rotation. After a rotation of the rotary latches  18  through about 100°, as per  FIG. 9 , the aeroplane door  2  is basically locked in the door frame  32 . The rotary latches  18  are rotated further until, as shown in  FIG. 10 , they are pivoted through an approximate angle of rotation α=180°. In this position the aeroplane door  2  is securely locked; however, in the event of an emergency it can be opened via a retraction of the rotary bars  22  in the longitudinal direction without any rotation of the rotary latches  18 . 
     For the regular opening of the aeroplane door  2  the rotary latches  18  are rotated in the opposite direction, such that the rotary latches  18  are moved back into their respective initial positions, and thereby release the rotary cylinders  26  that rotate with them. After the rotary cylinders  26  have been once again released the aeroplane door  2  is opened by means of a horizontal pivotal movement about the vertical axis in the opposite direction. 
     Disclosed is a locking mechanism for an aircraft door with a multiplicity of frame-side and door-side fittings, wherein the frame-side fittings have pins, on which in each case an eccentric rotary cylinder is mounted, and wherein the door-side fittings are designed as eccentric rotary latches to encompass sections of the rotary cylinders; also disclosed is a method for the closing and opening of an aircraft door without any rise and fall movement of the same. 
     LIST OF REFERENCE SYMBOLS 
     
         
         
           
               2  Aeroplane door 
               4  Locking mechanism 
               6  Outer skin 
               8  Interior structure 
               10  Vertical frame element 
               12  Vertical frame element 
               14  Horizontal frame element 
               16  Horizontal frame element 
               18  Rotary latch 
               20  Hole 
               22  Rotary bar 
               24  Kinematic system 
               26  Rotary cylinder 
               28  Pin 
               30  Foot section 
               32  Door frame 
               34  Rotary spring 
               36  Sickle-shaped claw 
               38  Eccentric holding fixture 
               39  Opening 
               40  Inner periphery 
               42  Outer periphery 
               44  Point of rotation for the rotary latch 
               46  Point of rotation for the rotary cylinder 
               48  Forces polygon 
             F Force 
             αAngle of rotation