Aircraft door

The present invention concerns a sliding door, which, for example, can be guided on three rollers on the door side in rails on the aircraft structure. Locking of such a cargo door occurs by movement of the cargo door parallel to the aircraft X-axis with the locking pins in corresponding sleeves situated on the aircraft structure. In order to guarantee this, the door opening must be larger than the door itself. The gap produced by this is now closed by means of a locking element that clamps the door. This permits a light structure of the cargo door and therefore a weight saving.

FIELD OF THE INVENTION

The present invention relates to an aircraft door and a corresponding method for opening an aircraft door.

BACKGROUND OF THE INVENTION

Conventional aircraft doors, for example, cargo doors, are opened upward by means of hydraulic cylinders via a hinge. Such cargo doors that can be tilted upward must be secured “failsafe” against unwanted falling down. This causes increased structural demands with additional weight. This also requires a very demanding locking mechanism. Such known cargo doors are also very wind-sensitive, so that the cargo door ordinarily can no longer be opened above a wind velocity of 40 knots.

SUMMARY OF THE INVENTION

Thus, there may be a need for an improved aircraft door for closing and opening in a shell of an aircraft.

According to an exemplary embodiment of the present invention an aircraft door is provided for closing and opening in a shell of an aircraft, in which the aircraft door can be moved along an essentially longitudinal direction of the aircraft. This may allow to provide for an aircraft door which, for example, has lower weight in comparison with known cargo doors.

Owing to the fact that the aircraft door is arranged in the open state in the wind shadow of the aircraft fuselage, the aircraft door is exposed to reduced loads. For example, a gust load is reduced. In addition, a load during failure of a hydraulic cylinder that can be provided for opening and closing or locking of the cargo door is reduced. Because of the reduced loads, a structural weight reduction may advantageously be produced, which can amount to a weight reduction of about 430 kg, for example, in a comparison calculation relative to an Airbus A300/600 cargo door. Owing to the fact that the aircraft door executes a movement along essentially the longitudinal direction of the aircraft and no rotational movement, for example, a simple guide and locking mechanism with few moving parts can also be implemented, which may again reduce maintenance requirements and weight of the locking mechanism. The wind sensitivity of the cargo door, relative to known cargo door variants that are tilted upward, is also advantageously reduced.

According to another embodiment of the present invention, the opening in the shell of the aircraft is larger than the aircraft door so that, in the aircraft door arranged in the opening, there is a gap between a first limitation of the aircraft door and a second limitation of the opening.

According to another embodiment of the present invention, this gap is closed by a first locking element in the closed state of the aircraft door. By inserting the first locking element into the gap between the shell and the aircraft door, the aircraft door can be securely locked.

According to another embodiment of the present invention, at least a second locking element is provided, so that the aircraft door is locked with a movement in the opening in the shell of the aircraft. This movement is essentially along the longitudinal direction of the aircraft. For example, a locking pin on the cargo door can be pushed into a corresponding receptacle in the shell of the fuselage of the aircraft. Advantageously, this may permit simple and secure locking. A very simple, robust and low-maintenance locking mechanism may also be made available on this account.

According to another embodiment of the present invention, the aircraft door is mounted on the fuselage or on the shell of the aircraft, so that the aircraft door is arranged for locking first in the opening. The aircraft door is then moved in the opening along the longitudinal direction of the aircraft for locking of the at least one second locking element. When the aircraft door is in the position in which it is locked by at least a second locking element, the gap between the shell of the aircraft and the aircraft door is closed by the first locking element, so that a second locking of the aircraft door is achieved. Particularly secure locking of the aircraft door may advantageously be possible on this account.

According to another embodiment of the present invention, the aircraft door is mounted by means of a guide rail, arranged in the shell of the aircraft, in which the mounting elements that are arranged on the aircraft door engage, so that it can be moved without rotational movement between the closed state and the open state.

As already discussed, this may advantageously permit simple guiding and mounting of the aircraft door.

According to another embodiment of the present invention, the guide rails and the mounting elements cooperate, so that guiding of the aircraft door along the longitudinal direction of the aircraft and relative to gravity is ensured.

According to another embodiment of the present invention, for opening of the aircraft door, the first locking element is first retracted, so that the aircraft door can be moved along the longitudinal direction of the aircraft for unlocking of the at least second locking element. As soon as the aircraft door is free, i.e., the at least second locking element is no longer locked, the aircraft door is then moved out of the opening along a normal to the shell of the aircraft, i.e., to the outside of the fuselage. As soon as the aircraft door is out of the opening, the aircraft door is pushed relative to the opening along the longitudinal direction of the aircraft, so that the opening is exposed. Advantageously, as already mentioned, the aircraft door executes no rotational movement, but is only guided along a linear movement.

Additional advantageous embodiments, especially a corresponding method for opening and closing of an opening in a shell of an aircraft, may be derived from the following description.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention is described below by means of a preferred exemplary embodiment of the present invention, namely, a cargo door. However, it is pointed out that the present invention is not restricted to use with a cargo door, but can also concern other hatches, passenger doors or similar aircraft doors.

FIG. 1shows a side view of a preferred practical example, namely, the cargo door according to the present invention. Reference number2inFIG. 1denotes the shell of the aircraft fuselage. Reference number4denotes the cargo door, arranged in opening6in shell2. The cargo door inFIG. 1is in the closed position. The reference number8inFIG. 1denotes a first locking element, which is also referred to here as closure. Opening6in shell2is defined by a door frame10, in which locking sleeves are arranged. Instead of locking sleeves in door frame10and the corresponding pins in door4, it is also possible to configure pins in the frame and sleeves on the door.

As can be deduced fromFIG. 1, the cargo door4has a smaller size than opening6. In this respect, the first closure element8is provided, which precisely closes the gap between opening6and cargo door4. In other words, the first closure element8matches the size of the gap between a cargo door4and opening6. When the cargo door4, as depicted inFIG. 1, is fully locked, which means it is in the fully closed position, the gap is closed by the first locking element8, so that the smallest possible intermediate space remains between opening6, on the one hand, and the first closure element8and cargo door4. Preferably, the door frame10, the first closure element8and the cargo door4are fit into the shell2of the aircraft fuselage, so that an almost seamless surface is produced. This permits swirling of the air flowing past to be avoided.

A cross section is defined inFIG. 1with the two arrows, denoted with the letters A. Different opening stages of cargo door4along this cross section A-A are depicted inFIG. 2ato2d.

The same reference numbers are used in the subsequentFIG. 2 to 17for the same or corresponding elements and assemblies.

FIG. 2ato2dshow different opening stages of cargo door4in a cross section along line A-A.

FIG. 2ashows the cargo door4in the closed state. As can be gathered fromFIG. 2a,the gap between shell2and cargo door4is closed by closure8. Cargo door4is locked on this account. Two second locking elements12are also provided inFIG. 21. These second locking elements12provide additional locking of cargo door4. The cargo door4is mounted on door frame10, especially by the second locking elements12.

FIG. 2adepicts the fully closed, locked state of cargo door4, for example, during operation of the aircraft, i.e., during flight.

FIG. 2bshows a first opening stage of cargo door4. For this purpose, as can be gathered fromFIG. 2b,the first closure element8(closure) moves from the gap to the inside of the aircraft fuselage. For example, the first locking element8can be tilted onto the inside of cargo door4, as shown inFIG. 2b.

FIG. 2cshows a second opening stage of cargo door4, which represents a later opening time in comparison with the first opening stage. As can be gathered fromFIG. 2c,the cargo door4has been moved along the longitudinal direction of the aircraft fuselage (the X-direction of the aircraft fuselage), so that the second locking clamps12have been unlocked. For this purpose, the freedom of movement of cargo door4in opening6is utilized and here through the gap, which is closed in the closed state by means of the first locking element. Accordingly, a gap width of the gap is closed by means of the first locking element8in the closed state, adjusted so that sufficient movement freedom for the cargo door4is made possible, to the extent that the second locking elements12are unlocked.

FIG. 2dshows a third opening stage of cargo door4. As shown with the arrows inFIG. 2d,the cargo door4is guided out of the opening to the outside of shell2. Preferably, this is achieved by means of movement along a normal to the shell2. The cargo door4is then pushed along the longitudinal direction of the aircraft, which is shown here with arrow14, so that the opening in the aircraft fuselage is exposed

As can be gathered fromFIGS. 2ato2d,locking of the cargo door4occurs by shifting the cargo door4with the second locking elements12parallel to the aircraft X-axis (longitudinal axis of the aircraft fuselage). The second locking elements12can be locking pins mounted on the cargo door, which engage in corresponding sleeves situated on the aircraft structure. In order to guarantee such locking, as already mentioned, the door opening must be larger than the cargo door4itself. The gap resulting from this now, in turn, serves as locking element, in which the first locking element8is used to close the gap. The door, which can still have movement freedom along the longitudinal direction of the aircraft after locking with the second locking elements12, is now firmly clamped in the door opening by the first locking element8. In order to permit such movement of cargo door4, the cargo door4is preferably configured as a sliding door. Such a sliding door is guided on three rollers on the door side in rails, which can be mounted, for example, on the aircraft structure. These are further described below.

FIG. 3ashows a three-dimensional view of the inside of cargo door4.FIG. 3bshows a three-dimensional side view of the cargo door of3a.As can be gathered fromFIGS. 3aand3b,the cargo door4is adapted to the camber of the fuselage. The locking elements on the door side, which engage in corresponding locking elements on the fuselage side for formation of the second locking element, are designed here as locking pins. As can be gathered fromFIG. 3a,upper locking pins42and lower locking pins42are provided. Guide rollers are also provided on the top and bottom of the cargo door4. An upper guide roller20, in particular, is provided and a lower guide roller24is provided, the upper guide roller20and the lower guide roller24being designed to ride in corresponding guide rails that are mounted on the fuselage (not shown). In addition, the cargo door4depicted inFIGS. 3aand3bhas center guide rollers26, which are formed in a corresponding center guide rail, which is mounted on the upper fuselage. Lateral locking pins22can also be provided on the cargo door4, which snap into or can engage in the corresponding grooves in the door frame10in opening6or in the first locking element8.

FIG. 4shows a three-dimensional view that depicts the opening, viewed from the cargo compartment of the aircraft. The cargo door mounts depicted inFIG. 4are configured, in particular, to guide or hold a cargo door4, as shown inFIGS. 3aand3b.This is described in more detail below.

As can be gathered fromFIG. 4, an upper guide rail30, a center guide rail32and a lower guide rail34are provided. The upper guide rail30and the lower guide rail34are arranged roughly along the opening in shell2of the aircraft fuselage. The center guide rail32is arranged in or on shell2, so that the cargo door4can be secured during opening. In particular, the cargo door is guided by the center guide rail32into the open position, in which the cargo door has been pushed rightward to the outside in the perspective depicted inFIG. 4. Practical examples of the center guide rail32are described in more detail below with reference toFIGS. 6 to 8.

As can be gathered fromFIG. 4, the upper guide rail30, the center guide rail32and the lower guide rail34are arranged essentially parallel to each other and essentially parallel to the aircraft longitudinal axis, i.e., the X-axis of the aircraft. Because of this, guiding and movement of the cargo door4along the longitudinal axis of the aircraft is made possible.

As can be further gathered fromFIG. 4, lateral locking sleeves36are provided in the door frame10that bounds the opening6, which cooperate, for example, with the lateral locking pins22(FIG. 3a) of cargo door4. Because of this, seating of the cargo door in the doorframe10can be made precise and fixed. In addition, lower locking sleeves38and upper locking sleeves40are provided in the doorframe, which cooperate with the upper and lower guide pins42(FIG. 3a) of the cargo door4to form a second locking element12.

FIG. 5shows a three-dimensional view, showing the arrangement and design of the upper locking sleeves40and the upper locking rails30in greater detail. As can be gathered fromFIG. 5, the upper locking sleeves40can be configured to engage with holes50, provided in equidistant vertical struts. The holes50are preferably arranged flush, so that the upper locking pins42of cargo door4(FIG. 3a) can be locked by a movement along the longitudinal direction of the aircraft.

FIG. 6shows a three-dimensional view of the outside of shell2of the aircraft fuselage with the center guide rails. As can be gathered fromFIG. 6, the center guide rail6has a region that is bent toward the inside, i.e., the aircraft interior, and extends into opening6. With this region extending into the aircraft interior, the guide rails32engage the center guide rollers26(FIG. 3a) of the cargo door4when the cargo door is fully locked (which means the first and second locking elements are locked). The cargo door4is also engaged with this inward-facing region of the guide rails32, as long as the cargo door4moves in the plane of shell2. In particular, this is the case when the second locking elements12are unlocked. If the cargo door is moved from opening6to the outside of the aircraft fuselage, the center guide rollers26roll on the center guide rails32along the outside of the aircraft fuselage, until the cargo door4is in the fully opened position, in which the cargo door opening6is essentially exposed.

FIGS. 7 and 8show cross sections of preferred practical examples of the center guide rails32. As can be gathered fromFIG. 7, the guide rail32is arranged on the shell2by means of a reinforcement element58. In contrast to this, the guide rail32in the practical example ofFIG. 8is embedded in shell2by means of another reinforcement element60. In the practical example ofFIG. 8, it can be necessary that structural changes to the shell are required in the region of the center guide rail32.

FIG. 9shows a three-dimensional detail of the lower guide rail34. As can be gathered fromFIG. 9, the lower guide rail34is provided essentially parallel to the lower edge of opening6. The lower locking sleeves38are essentially functionally equivalent to the upper locking sleeves40. The lower guide rail34and the upper guide rail30, as well as the center guide rail32, are preferably arranged, so that they provide parallel guiding of cargo door4, so that the cargo door is guided linearly.

FIGS. 10ato10dshow three-dimensional views of opening stages of cargo door4according to a practical example of the present invention.FIG. 10ashows the fully locked state, in which both the first locking element8and the second locking element12(consisting of pin42and upper locking sleeves40) are locked. In the state depicted inFIG. 10d,the first locking element8is completely retracted, so that the cargo door4could be moved along the longitudinal axis of the aircraft, in order to unlock the second locking elements. As can be gathered fromFIGS. 10ato10d,the first locking element8is pulled from the gap, so that the cargo door4has freedom of movement within opening6, so that it can execute a leftward movement along the longitudinal axis of the aircraft, so that the second locking elements12can be unlocked.

FIGS. 11ato11dshow the unlocking states depicted inFIG. 10ato10dfrom a different perspective. As can be gathered fromFIGS. 11ato11d,the first locking element8is removed from the gap toward the inside of the aircraft fuselage. The locking element8, as shown inFIG. 11d,is then moved behind cargo door4, as could already be deduced fromFIG. 2b.In this respect, a separate guiding or holding of the first locking element8on the inside of cargo door4can be provided.

FIG. 12ashows a three-dimensional view, showing the locked second locking elements.FIG. 12bshows a detail view ofFIG. 12a.FIGS. 12aand12bshow a state, in which the second locking elements are locked, i.e., the locking pins42are fully inserted into the upper locking sleeves.FIGS. 13aand13bshow the views corresponding toFIGS. 12aand12b,but the second locking element inFIGS. 13aand13bis unlocked, i.e., as can be gathered, especially froFIG. 13b,the upper locking pin42is removed from the locking sleeve40.

FIGS. 14ato14cshow three-dimensional detail views of the upper guide rails30of the upper locking sleeves40and the arrangement of the cargo door4in shell2.

As can be gathered fromFIGS. 14ato14c,the cargo door in these figures is in a state, in which the second locking elements are fully unlocked, and the cargo door can now be moved outward, as shown in the corresponding views ofFIGS. 15ato15c,to then be pushed out laterally along the fuselage.

FIG. 16shows a three-dimensional view of the outside of the aircraft fuselage with the fully opened cargo door4. As can be gathered fromFIG. 16, the cargo door4is preferably movable far enough to the outside of the aircraft fuselage under the guidance of at least the center guide rail32, that the entire opening6in the aircraft fuselage is freely accessible.

With the aforementioned arrangement of the cargo door4, as soon as cargo door4has been pushed outward from opening6in shell2, it can be pushed collision-free along the outside of the fuselage.

The invention described above preferably permits a simple locking mechanism that gets by with few moving parts. This permits near freedom from maintenance of the cargo door, and also low weight. This also reduces the vulnerability to defects of the locking mechanism. Because of reduced loads from gust loads or failure of a hydraulic cylinder, a structural weight reduction of the cargo door can be achieved that can provide a total weight advantage of about 430 kg, for example, in a comparison calculation relative to the now common Airbus A300/600 cargo door.