Abstract:
The invention relates to a door lock comprising a door catch system for double door-type helicopter doors that can, when being closed, additionally be displaced perpendicularly to the plane of the door opening into the closed position (flush fitting). Said door lock comprises a catch element ( 30 ) associated with the latch element ( 31 ) and actively linked therewith, said catch element maintaining the door ‘caught’ directly in front of its locked position when the door is manually closed until the door is translated to its final closed position via the latch element ( 31 ).

Description:
TECHNICAL FIELD 
     The invention relates to a door lock for doors of aircraft, especially of helicopters. 
     BACKGROUND 
     These doors are conventionally made as folding doors for boarding of pilots. Differently than in ground vehicles, in aircraft the doors present there within the openings provided in the fuselage structure must be absolutely securely closed—filled in—whereby for the necessary sealing, there are so-called gas compression springs generally between the door and door opening. 
     Closing of these doors therefore requires three successive manual manipulations, specifically pulling the door shut, holding the door in this state, and then locking it. To do this, the door structure is connected to several door locks whose tumblers that interact with catches attached to the fuselage structure can be jointly actuated by way of a suitable linkage that has a handle. Therefore, when these doors are closed, a considerable expenditure of force is necessary for the last two manipulations since the respective door when locking must be held relatively tightly shut. If the door is not shut strongly enough, it can happen that as a result of the force of the gas springs, one tumbler or another engages “space,” and therefore the pertinent door is not properly locked. Moreover, generally both hands of the pertinent person are needed to close the door. 
     Previously known door locks of locking devices for these doors are obviously user-unfriendly. For opening the door, as long as the pertinent individual is standing in front of the helicopter, there is enough room and freedom of motion for opening and closing the door, and pulling, pressing and turning the handle can be done without major difficulties. This changes immediately, however, after boarding and sitting down in the helicopter; due to the limited ergonomy and the fact that the pilots&#39; seats are made adjustable forward and up depending on body size, operation of these doors becomes many times more difficult. 
     The doors of a helicopter constitute the first contact with the aircraft and thus determine the first impression on the respective user: there is therefore the requirement that the doors be made self-explanatory in terms of their operability and function and that they not already form the first manual and/or technical obstacle when boarding the helicopter. The functions of door locking should likewise be understandable and logical to anyone, without additional signs and instructions. 
     A generic door locking device for helicopter doors is available and in use for the helicopter Eurocopter EC 135 as special equipment. 
     DE 37 07 323 A1 discloses a door locking system, especially for a helicopter door, with two cradle locks that operate in opposite directions, by which the door folds in the closed position are automatically centered with respect to the door frame and braced by compression or tension with the door frame in the direction of the two-dimensional extension of the door fold. The disadvantage here is that the door folds must be held in the closed position when being locked so that two hands are necessary for a closing process. 
     DE 103 59 737 A1 discloses a device for locking the hood of a motor vehicle. The device has at least one main closure and at least one auxiliary closure that each comprise a latch with a ratchet and a latching member that can be locked by the latch in the closed position of the hood. To initially limit the opening travel of the hood, the latching member of the auxiliary closure is made such that with the main closure unlocked, only after intentional opening travel of the hood does the locking action between the latching member and the latch of the auxiliary closure begin. In this connection, it is disadvantageous that in the half-engaged position, i.e., after activating the latch, a gap remains between the hood and body. 
     SUMMARY 
     The object of the invention is therefore to devise a new door locking device that can be better operated than in the past while preserving closing safety. 
     Proceeding from a door locking system of the initially named type, this object is achieved according to the invention. 
     Other features of the invention will become apparent from the dependent claims. 
     The new door locking system is surprisingly advantageous. 
     Using the catch hook according to the invention that is dynamically connected by gearing to the locking hook, specifically before the locking hook takes effect, the pertinent door made as a folding door is “caught” in the closed position in which the locking hook is only in the region of the catch so that simply by continuing to move the locking hook into its closed position by way of the indicated handle, the door can be transferred into its final closed position without the necessity of manually holding/tightening/pressing the door into the opening present in the fuselage structure. When the locking hook is transferred into its final closed position, by way of the kinematic connection that according to the invention is made as a spring-loaded pivoting wedge that is located perpendicular to the pivoting axis of the locking and catch hooks, the catch hook is released again for a new closing process. The wedge surface and catch step of the pivoting wedge are located on its action surface that faces the end regions of the catch and locking hooks, whereby the pivoting wedge—on which the torsion spring acts in the counterclockwise direction with respect to its bearing bolts as soon as the catch step is dynamically connected to an extension of the catch hook—blocks the latter in its position in which contact with the stop pin has been made. 
     The execution of the door locking system according to the invention greatly facilitates reliable closing of these doors and therefore increases the ease of operation for the helicopter crew. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described below using one exemplary embodiment that is shown more or less schematically in the drawings. 
       Here: 
         FIG. 1  shows an isometric view of a locking device intended for a folding door of a helicopter according to the invention, 
         FIG. 2  shows a top view of the locking device according to  FIG. 1 , 
         FIG. 3  shows a side view of the locking device according to  FIG. 1  in the direction of arrow A, 
         FIG. 4  shows a side view of the locking device according to  FIG. 1  in the direction of arrow B with the carrier plate that bears the locking elements, and 
         FIG. 5  shows a side view of the locking device according to  FIG. 1  in the direction of arrow C. 
     
    
    
     DETAILED DESCRIPTION 
     Of a locking device for the folding door of an aircraft, neither of which are shown, especially of a helicopter,  FIGS. 1 to 5  show only one of the locking devices  10  that is tightly connected to the folding door and that can be actuated by way of linkage that has a hand lever and that likewise is not shown, and can interact with one fitting at a time that is used as the catch  11  and that is attached to the fuselage structure of the aircraft. 
     Each of the locking devices  10  has an angular carrier plate  12 , whose part that is bent by roughly 90° forms a flange  13  that is located obliquely—see FIG.  4 —to the roughly horizontal action plane of the locking device. The respective locking device is attached to the folding door of the helicopter by way of the flange  13  by means of screws that are not shown here. 
     The flange  13  carries a bearing bolt  15  for a pivotally mounted pivoting wedge  16  upon which a torsion spring  17  acts in the counterclockwise direction; compare  FIG. 1 . A plate-shaped extension  18  of the carrier plate  12  carries a bearing bolt  19  for holding the latch elements that are still to be described and on its free end has a slotted opening  22  that faces the bolt  20  of the catch  11 . The rear edge  23  of the slotted opening  22  is used as a stop and thus as a limit of the motion of the folding door into its closed position. The pivoting wedge  16  extends through an opening  24  provided in its region in the extension  18  of the carrier plate  12  into the pivoting region of the latch elements that are still to be described. 
     The pivoting wedge  16  for purposes of guidance in the opening  24  of the carrier plate  12  has a lateral extension  26  that with the front side of the free end of the pivoting wedge forms a common wedge surface  28 ; compare  FIG. 5 . Furthermore, laterally offset to the wedge surface  28  is a catch step  29 —FIG.  2 —which, as will be described below, is used for temporary locking of one of the latch elements. 
     The indicated latch elements comprise a catch hook  30 , made as a double-armed lever, and, adjacent to it, a locking hook  31 —that acts as a latch—that is likewise made as a double-armed lever and that acts as a so-called latch, and that are both pivotally supported on the bearing bolt  19  of the carrier plate  12 . A torsion spring  34  acts on the catch hook  30  in the clockwise direction with reference to the bearing bolt  19 —compare  FIG. 1 . The motion of the catch hook  30  in the counterclockwise direction is limited by a stop pin  32  that is attached in the plate-shaped extension  18  of the carrier plate  12 . The catch hook  30  on its free end facing the bolt  20  has a slotted opening  36  that is pointed down and whose limit stop facing the bolt runs out in a wedge surface  37 . The lever arm of the catch hook, which arm faces away, bears an extension  38  that faces the carrier plate and that interacts with the catch step  29  of the pivoting wedge  16 ; compare  FIG. 2 . 
     The free end of the double-armed locking hook  31  facing the bolt  20  likewise has a slotted opening  39  that on its free end passes into a wedge surface  40 ; compare  FIG. 3 . The indicated wedge-surfaces  36  and  39  of the pertinent latch elements, specifically the catch hook  30  and the locking hook  31 , support the catching and locking motion of the latch elements in the clockwise direction around their bearing bolts by way of the bolt  20  as soon as the folding door is transferred by hand into a position near the closing position. 
     The lever arm of the locking hook  31 , which arm faces away, bears a hinge pin  43  that is provided with a ball head  42 —compare FIG.  2 —that by means of a sleeve  44  projects into the pivot region of the catch and locking hooks, and into the region of the wedge surface  28  of the pivoting wedge  16  in order to move the latter, as will be described. 
     The above-described locking device works as follows: 
     As already mentioned, as soon as the folding door is moved into the closed position by way of the wedge surface  28 , the catch lever  30  is pivoted by the bolt  20  relative to  FIG. 3  in the clockwise direction around the bearing bolt  19  against the action of the spring  34  by a small angular amount. In this connection, the catch hook with its opening  36  of one lever arm encompasses the bolt  20  and with its other lever arm that faces away moves the pivoting wedge  16  by means of its extension  38 —FIG.  2 —opposite the action of the spring  17  in the clockwise direction until the illustrated blocking position is reached, in which the pivoting wedge  16  and catch hook  30  are locked to one another by way of the catch step  29  of the pivoting wedge and the extension  38  of the catch hook, which extension is acting there. Thus, the folding door is held in the position that it has just assumed—is thus “caught.” If at this point the locking hook  31  is moved around the bearing bolt  19  with respect to  FIG. 3  in the clockwise direction by way of the linkage that is not shown by means of its hand lever—that so far has assumed its normal position and at this point is moving into the closed position—the locking hook  31  with its slotted opening  39  thus now completely encompasses the bolt  20  and—with simultaneous tightening of the door fold in its door opening within the fuselage structure of the helicopter—locks the latter in the closed position. To do this, the locking hook  31 , as already mentioned, on its free lever arm bears the bolt  43  with the ball head  42  that is dynamically connected to the indicated linkage for locking the door. During movement of the locking hook  31  into the blocking position, it moves, as the result of its travel that is chosen to be greater compared to the catch hook  30 —according to the greater length of the lever arm relative to the bearing bolt  19 —compare FIG.  2 —the pivoting lever  16  out of its blocking position and thus by way of the extension  38  releases the catch hook  30  for a new process when the folding door is closed again. Due to the greater travel of the locking hook  31 , specifically beginning at a certain angular position, the pivoting wedge  16  is pivoted so far that the spring-loaded catch hook  30  that is released in doing so can pivot back again into its initial position for a new catch process when the folding door is closed. 
     REFERENCE NUMBER LIST 
     
         
           10  locking device 
           11  catch 
           12  carrier plate 
           13  flange 
           15  bearing bolt 
           16  pivoting wedge 
           17  torsion spring 
           18  plate-shaped extension 
           19  bearing bolt 
           20  bolt 
           22  slotted opening 
           23  rear edge of the slotted opening 
           24  opening 
           26  lateral extension 
           28  wedge surface 
           29  catch step of the pivoting wedge  16   
           30  double-armed catch hook 
           31  double-armed locking hook 
           32  stop pin 
           34  torsion spring 
           36  slotted opening 
           37  wedge surface of the catch hook 
           38  extension of the catch hook 
           39  slotted opening 
           40  wedge surface of the locking hook 
           42  ball head 
           43  hinge pin 
           44  sleeve