Door for aircraft, particularly for helicopter, with interconnected movements of upper and lower leaves

A door is provided for an aircraft. The aircraft includes a cabin having a floor and a roof. The door includes an upper and lower leaves hinged along axes approximately parallel to a longitudinal axis (X--X) of the aircraft. The leaves can swing between an open position in which each of the two leave projects outwards from the cabin and a closed position in which the two leaves are folded down on the cabin and are fixed with the cabin by locking device. The door further includes interconnecting mechanisms for connecting the two leaves to each other so that when one leaf is moved between the open and closed positions the other leaf will also move. A stopper holds one of the upper and lower leaves in the open position when the interconnecting mechanism disposes the stopper in an extended position. A driver is provided for moving one of the leaves from its closed position to its open positions The driving of one of the leaves, through the interconnecting mechanism, also moves the other of the two leaves to the open position. The driver includes a mechanism for sufficiently setting the lower leaf in motion toward the open position so that the lower leafs own weight further continues the lower leafs motion to the open position.

FIELD OF INVENTION 
The present invention is directed to a door opening device for an aircraft 
which includes a cabin comprising a floor and a roof. The door includes an 
upper leaf and a lower leaf hinged along axes approximately parallel to a 
longitudinal axis of the aircraft, swingable an open position in which 
each of the two leaves projects outwards from the cabin and a closed 
position in which the two leaves are closed down on the cabin and are 
fixed to it by locking means. 
BACKGROUND OF THE INVENTION 
The invention relates in particular to the doors for an aircraft, 
particularly for a helicopter, enabling the pilot and the passengers to 
get into and get out of them. Doors are known which are composed of two 
leaves which open respectively upwards and downwards, towards the outside 
of the aircraft. 
Even if the doors enable distributing the forces on the whole of the fixing 
points of the two leaves on the helicopter cabin as well as minimizing 
being held by the wind in comparison with a door composed of only one 
leaf, the opening and closing of such doors is longer and more tiresome 
since it is necessary to handle each of the two leaves one after the other 
and in precise order in order to carry out a closing ensuring the safety 
of the aircraft in flight. 
Furthermore, the lower leaf of such doors requires the use of a landing 
skid on which is fixed a step of significant bulk. This is harmful to the 
aerodynamics of the aircraft. 
The invention has the objective of solving the disadvantages mentioned 
above by proposing a door with two leaves for which the opening and 
closing are made easier and which ensures an access for the passengers to 
board the cabin without requiring bulky steps. 
SUMMARY OF THE INVENTION 
To this end, in accordance with the invention, an opening system of the 
aforementioned type is mainly characterized in that it includes: 
means of interconnecting the movement of the two leaves between each of the 
open and closed positions; and 
means forming a stop for one of the upper and lower leaves in the open 
position, the aforementioned means forming a stop being opened out in the 
open position by the interconnecting means. 
The opening device in accordance with the invention can possibly comprise 
in addition one or more of the following characteristics: 
the device includes driving means of one of the leaves from its closed 
position to its open position with the result that, the opening movement 
of one of the leaves drives, through the interconnecting means, an opening 
movement of the other of the two leaves; 
the driving means include means for setting in motion the opening movement 
of the lower leaf, which movement being then continued under the action of 
the own weight of the aforesaid leaf, thus driving the opening of the 
upper leaf; 
the interconnecting means include: 
a guide rail fixed with a vertical upright of the door frame; 
a guide runner mounted to slide in the guide rail; 
an upper rod, a first end of which is hinged on an edge of the upper leaf 
and a second end of which is hinged on the aforesaid guide runner, the 
aforesaid edge and the aforesaid vertical upright being opposite when the 
upper leaf is in the closed position; 
a system of rods hinged on the one hand on the aforesaid vertical upright 
and on the other hand on an edge of the lower leaf; 
a supple link, a first end of which is fixed on the guide runner, and a 
second end of which is fixed on the system of rods; and 
means of return of the supple link installed on the vertical upright in 
order to link the movements of the upper leaf to the movements of the 
lower leaf; 
the device includes a gas rod, a first end of which is fixed to the guide 
runner, and a second end of which is fixed with the vertical upright in 
order to promote the opening movement of the upper leaf and to hold it in 
the open position; this gas rod is optional because it only requires the 
hinge moment of the weight of the lower leaf to be greater than that of 
the upper leaf in order that the opening can be easily done; 
the system of rods includes first and second lower rods which are hinged to 
each other and which include respectively one end hinged on the vertical 
upright and one end hinged on the edge of the lower leaf; 
the second end of the supple link is fixed at a point of the first lower 
rod; 
the means of return of the supple link include two pulleys fixed on the 
vertical upright, respectively above the guide rail and the hinge point of 
the end of the first lower rod on the aforesaid vertical upright; 
the pulley fixed above the guide rail is fixed by suspension means so as to 
absorb the play of the supple link as well as the adjustment and 
manufacturing gaps; 
the second end of the upper rod is sliding mounted on this rod and elastic 
means are interposed between the second end of the upper rod and the rest 
of this rod so that, during closing of the upper leaf, the upper rod 
occupies successively: 
a first stable equilibrium position when the upper leaf is half open, a 
position in which the elastic means are not compressed, 
an unstable equilibrium position in which the elastic means are compressed, 
the upper leaf being in a quasi-closed position in which a point of the 
axis of rotation of the upper leaf on the cabin, the first end of this rod 
and the guide runner abutted in the bottom of the guide rail are aligned; 
and 
a second stable equilibrium position in which the upper leaf is in the 
closed position, the elastic means being less compressed than in the 
unstable equilibrium position; 
the means for setting in motion the opening movement of the lower leaf 
include a torsion spring interposed between the hinged together ends of 
the two lower rods; 
the means forming the stop includes a prop movable between a retracted 
position when the lower leaf is in the closed position and in which the 
prop is housed in the lower leaf, and an opened out position when the 
lower leaf is in the open position and in which the prop is abutted on the 
cabin; 
the prop includes an internal end rotary mounted in the lower leaf and an 
external end free to abut against the cabin, torsion means connecting the 
internal end of the prop to the end of the second lower rod hinged on the 
lower leaf, in order to make the rotational movement of the prop 
proportional to the rotational movement of the lower leaf; 
the torsion means includes a torsion tube a first end of which rotates with 
the end of the second lower rod and a second end of which engages with a 
pin on which is fixed the prop, the torsion tube and the prop having 
perpendicular axes; 
the second end of the torsion tube comprises a radial recess extending over 
a part of the circumference of the torsion tube and in which penetrates 
means forming a key mounted on the pin so that, during closing and opening 
movements of the lower leaf, the torsion tube rotates the pin on only a 
part of its rotation; and 
a torsion spring is carried by the pin, one end of this spring being fixed 
to the lower leaf and another end being fixed to the pin, so that the 
closing movement of the lower leaf causes compression of the spring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a front door 1 for a helicopter. This helicopter (not shown) 
includes, in a known way, a cabin 21 provided with a roof 23 and a floor 
22 (shown in part in FIGS. 4 and 5). In addition, the door 1 is composed 
of two leaves, an upper leaf 2 and a lower leaf 3, each hinged along an 
axis parallel to a longitudinal axis X--X of the helicopter, near the roof 
23 and the floor 22 respectively. 
As it is more particularly shown in FIG. 2, each of the two upper and lower 
leaves opens respectively upwards and downwards toward the outside of the 
helicopter cabin along the arrows F. In the closed position, the lower 
leaf 2 is folded down on the upper leaf 3 and is held in the closed 
position on the cabin by locking means 4 in itself known, such that a rod 
penetrates into a door frame 5, and particularly in vertical uprights 6 of 
this frame. 
In addition, the opening and closing movements of the two leaves 2 and 3 
are connected by an opening device 7 which includes interconnecting means 
8 of the movement of the two leaves 2 and 3 as well as a stop means 9 for 
forming a stop for the lower leaf 3 against the cabin 21 when it is in the 
open position. 
The interconnecting means 8 are now to be described in comparison with 
FIGS. 1 and 3 to 5. They include a guide rail 10 fixed on the vertical 
upright 6 of the door frame 5 and in which is slidingly mounted a guide 
runner 11. 
The interconnecting means 8 include in addition an upper rod 12 which has a 
first end 13 hinged on an edge 14 of the upper leaf 2 and a second end 15 
which is hinged on the guide runner 11. 
The upper leaf 2 is shown in FIG. 4 on the one hand, in the open position 
as chain dotted lines and on the other hand, in the closed position as 
continuous lines. 
It is thus understood that when this leaf 2 is in the closed position, the 
guide runner 11 is abutted in a bottom 16 of the guide rail 10, the upper 
rod 12 being then approximately parallel to the vertical upright 6. When 
the upper leaf 2 is brought into the open position, the guide runner 11 
slides in the rail 10 to be abutted at the top in this rail and thus 
retain the leaf 2 in the open position, projecting outwards from the 
cabin. 
A gas rod 18 is on the one hand fixed by a first end 19 to the guide runner 
11 and by a second end 20 to the vertical upright 6. This rod 18 enables 
promoting the opening of the upper leaf 2 and holding it in the open 
position as a result of the force which the rod exerts on the guide runner 
11, and therefore, by means of the upper rod 12, on the upper leaf 2. 
FIG. 5 shows that the opening device 7 in accordance with the present 
invention includes in addition a system of rods 25 which is on the one 
hand hinged on the vertical upright 6 of the cabin, near the floor 22 and, 
on the other hand, on an edge 26 of the lower leaf 3. 
The system of rods 25 includes a first lower rod 27 and a second lower rod 
28 hinged to each other so as to form torque links. The first rod 27 is 
hinged by a first end 29 to the vertical upright 6 whereas the second rod 
28 is hinged by a second end 30 on the edge 26. 
The two lower rods 27 and 28 comprise driving means 32 intended to cause 
the opening of the torque links composed of these two rods and therefore 
to cause the opening movement of the lower leaf 3 from its closed position 
(shown in continuous lines) to its open position (shown in chain dotted 
lines). 
These driving means 32 include means 33 for setting in motion the opening 
movement of the lower leaf 3 which continues then under the sole action of 
the weight of this leaf. The setting in motion means 33 consist of a 
torsion spring having two ends respectively supported against each of the 
ends, which are hinged together, of the two lower rods 27 and 28, this 
spring being under tension when the torque links is closed, i.e. when the 
lower leaf 3 is in the folded down position on the cabin 21. 
The opening device 7 includes moreover a supple link 35 passed on return 
means 36 which includes a first pulley 37 fixed on the vertical upright 6, 
in a point located above the guide rail 10 and a second pulley 38 fixed on 
the same upright, above a hinge point 40 of the first lower rod 27 on the 
upright 6. 
The supple link 35 has a first end 41 fixed on the guide runner 11, is 
passed on the first pulley 37 in order to be returned to the second pulley 
38 and be fixed by a second end 42 in a point A located on the length of 
the first lower rod 27. 
In order to absorb the plays of the supple link 35, which takes for example 
the form of a cable, as well as the adjustment and manufacturing gaps, the 
first pulley 37 is fixed to the upright 6 by suspension means 43. 
Thus, when the two upper 2 and lower 3 leaves of the door 1 are to be 
opened, a user unlocks the locking means 4, the torsion spring 33 then 
gives an impulse causing the separation of the two lower rods 27 and 28, 
this causes setting in motion the opening movement of the lower leaf 3, 
this movement continuing then under the action of this leave's own weight. 
The lower leaf being connected to the upper leaf 2 by the supple link 35, 
the downwards movement of this lower leaf causes a downwards displacement 
of the second end 42 of the supple link 35 and consequently an upwards 
movement of the first end 41 of the aforesaid link. This first end drives 
the guide runner 11 which then slides in the guide rail 10, thus driving 
the upper rod 12 and therefore causing the opening of the upper leaf 2. 
The opening movement of this upper leaf is accompanied by an opening out of 
the gas rod 18 which promotes this movement and which holds the upper leaf 
2 in the open position. This rod enables also the adjustment of the speed 
of opening and the dampening of the limit of the travel. 
When a user wishes to close the two upper 2 and lower 3 leaves, it is 
sufficient that he folds down the upper leaf 2 toward the cabin 21. This 
movement causes a downwards displacement of the end 41 of the supple link 
and therefore an upwards movement of the second end 42 of this link. The 
position of the two pulleys 37 and 38 as well as the length of the cable 
35 are adapted so that the lower leaf 3 comes into the closed position 
some time before the upper leaf 2. It is sufficient then to lock the upper 
leaf 2 on the cabin by means of the locking means 4 for the door 1 to be 
closed in a sure manner. 
In addition, in order to ensure good closing of the upper leaf 2, the 
second end 15 of the upper rod 12 is movably mounted on the running part 
of the aforesaid rod. This end 15 is sliding mounted on the rest of the 
rod 12 and is biased against the first end 13 by elastic means 50. These 
means take for example the form of Belleville washers mounted head to tail 
in order to constitute a spring which is compressed when the second end 15 
tends to be forced toward the first end 13. 
Thus, the elastic means 50 enable the user to feel "a hard point" during 
closing of the upper leaf 2 onto the cabin. Indeed, when the leaf 2 is in 
the half open position, the elastic means 50 are not compressed and the 
leaf is then in a stable position. When the user continues the closing 
movement, the upper leaf 2 passes through a position in which a point B of 
the axis of rotation of the upper leaf 2 on the cabin, the first end 13 
and the guide runner 11 are aligned, a position in which the elastic means 
50 are compressed. In order to completely close the upper leaf 2, the user 
causes a slight additional rotation of this leaf, this causes a release of 
these means 50 with the result that the upper leaf 2 is pressed against 
the cabin and the user feels a "pulling" of this leaf. 
Finally, the stop means 9 of the lower leaf 3 against the cabin 21, when 
this leaf is in the open position, include a prop 55. This prop is movably 
mounted on the lower leaf 3 between a retracted position in which the prop 
is completely housed in the leaf 3 when this leaf is in the closed 
position and an extended position in which the prop 55 is abutted against 
the cabin 21 when the leaf is in the open position. 
The prop 55 is thus rotary mounted by a first internal end 56 which is 
hinged on the lower leaf 3 and is abutted by an external free end 57 
against the cabin 21. 
In order to make the rotational movement of the prop 55 proportional to the 
rotational movement of the lower leaf 3, torsion means 60 connect the 
internal end 56 of this prop to the end 30 of the second lower rod 28 
which is hinged on the lower leaf 3. 
As is shown more particularly in FIG. 6, the torsion means 60 include a 
torsion tube 61 which has a first end 62 connected to the aforesaid end 30 
and a second end 63 engaging a pin 64 on which is fixed the prop 55, so 
that the prop 55 and the tube 61 are perpendicular, the aforesaid tube 
extending longitudinally in the lower leaf 3. 
The second end 63 of the torsion tube 61 has a radial recess 65 (FIG. 7) 
which extends over only a part of the circumference of this tube. This 
recess 65 is passed through by a key 66 mounted on the pin 64 so as to fix 
this pin of the tube 61 on only a part of the rotation of this tube. 
In addition, the pin 64 carries a torsion spring 67 one end of which is 
fixed to the lower leaf 3 and the other end of which is fixed to this pin. 
During the closing movement of the lower leaf 3, the end 30 of the second 
lower rod 28 rotates the torsion tube 61 in the clockwise direction. The 
length of the radial recess 65 is such that the end 63 of the tube 61 
abuts against the key 66 only after the lower leaf 3 has traveled half of 
its rotation path, i.e. when the tube 61 has also traveled half of its 
rotation path. After this abutting, the tube 61 and the pin 64 rotate 
integrally (FIG. 7), the end of the rotation path of the tube then 
compresses the torsion spring 67 and causes rotation of the prop 55 in 
order for it to be retracted in the lower leaf 3. 
In the opposite movement, i.e. during opening of the lower leaf 3, the 
torsion spring 67 holds the pin 64 to rotate integrally with the torsion 
tube 61 on half of the rotational path of the leaf 3, and therefore on 
half of the rotation of the tube 61. The prop 55 is thus opened out before 
the lower leaf 3 has finished its rotational path to its open position. 
The prop 55 is therefore properly opened out to abut, with its external 
free end 57, against the cabin 21. 
The abutting of the lower leaf 3 by means of the prop 55 enables giving the 
lower leaf 3 in the open position the function of a step 60. The lower 
leaf 3 is in addition shaped so that the step 60 occupies the function of 
an armrest for a pilot or a passenger when the lower leaf 3 is the closed 
position.