Aeronautics and astronautics – Aircraft structure – Details
Reexamination Certificate
2002-12-16
2004-02-03
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Aircraft structure
Details
C049S246000, C091S402000
Reexamination Certificate
active
06685139
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTION
This application claims the priority of Application No. 101 61 562.0, filed Dec. 14, 2001, in Germany, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a gas-operated emergency opening cylinder having a piston rod for swivelling a passenger door of an airplane, the emergency opening cylinder being a component of an emergency opening system of the passenger door, and the emergency opening cylinder being arranged on a carrying arm bearing and carrying the door, and the piston rod being connected with the door, and the emergency opening cylinder having a ventilation bore in the end area of its cylinder space through which the piston passes.
The passenger door of an airplane is movably connected with a carrying arm by way of two fittings, for example, triangular control arms. The opposite end of the carrying arm is swivellably disposed in a fuselage-side frame. During the opening operation, the passenger door is lifted after the unlocking operation and, from the end of the lifted position, is swiveled into an opening position to a stop. In this case, the door is swiveled out of the opening of the fuselage. The emergency opening cylinder corresponds to an actuator which is held and disposed at the carrying arm, and its piston rod is connected with the interior side of the passenger door by means of a separate fitting.
The passenger plane has an emergency opening system for the passenger door. In the event of an emergency landing, it has to be possible to open the passenger door within a few seconds and an emergency slide has to be moved out at the door. Such an emergency opening of the passenger door takes place by means of a gas-operated actuator on the carrying arm which, by way of a lever mechanism, changes the passenger door from the end position of the lifting operation into a swivelling movement and carries out this swivelling movement to a stop. This actuator has a gas reservoir. The compressed gas stored there has the energy required for an emergency opening operation of the passenger door. When the gas tank of the actuator is opened, the gas flows into a cylinder of the actuator. This is the emergency opening cylinder. The piston with the piston rod arranged in the cylinder is moved as the result of the gas pressure, and the piston rod starts to swivel the passenger door into the opening position. After the end of the lifting movement of the piston rod, the piston has reached a position in the cylinder where it opens up a bore in the cylinder wall. This ventilation bore connects the cylinder space with the outer atmosphere, so that the gas can escape into the atmosphere. The ventilation bore in the emergency opening cylinder is required in order to be able to close the passenger door without any significant expenditure of force after the emergency opening has taken place. Emergencies considered so far are controllable.
In the event of an emergency landing with a left-hand breakage of the landing gear, the passenger door or similar device (service door or emergency exit door) arranged on the left fuselage side can be opened up at a low expenditure of force to a swivelling angle of 90° (movement along the force of gravity). Viewed in the flying direction, the left-hand fuselage side is defined as the left fuselage side. After a swivelling angle of 90°, the door must then be opened against the force of gravity. This requires an emergency opening cylinder which will function also in this case. In the case of the previous operating characteristic of the emergency opening cylinder, the gas pressure and thus the available opening force had already fallen toward the 0 value at a door opening angle of 120°. The cause was the opening-up of the ventilation bore by the piston and the escape of the gas into the atmosphere.
Because of the possible inclination in the case of a one-sided and left running gear breakage in the case of an emergency landing, starting at an opening angle of 90°, the door has to be opened against the force of gravity. This means that the existing piston rod of the emergency opening cylinder requires an additional increased force in its previous end area.
An actuator (emergency opening cylinder) is required which, particularly in the last path section of the piston with the piston rod, can accelerate against the force of gravity.
The exchange of the known emergency opening cylinder against an energetically intensified emergency opening cylinder would be obvious but has the disadvantage of an increased weight and of higher costs.
It is an object of the invention to adapt the existing emergency opening cylinder at the lowest expenditures and with an insignificant change of weight with respect to its operating characteristic to the load situation of an emergency opening of a passenger door against the force of gravity.
In the case of an emergency opening cylinder of the above-mentioned type, this object is achieved by providing a gas operated emergency opening cylinder having a piston rod for swivelling a passenger door of an airplane, the emergency opening cylinder being a component of an emergency opening system of the passenger door, the emergency opening cylinder being arranged in use on a carrying arm bearing and carrying the door with the piston rod being connected with the door, the emergency opening cylinder having a ventilation bore in an end area of its cylinder space through which the piston rod passes, wherein the ventilation bore leads into a collecting chamber which has an outlet valve controllable by a control.
In a mouth area of the ventilation bore, a collecting chamber is arranged which has a controllable outlet valve, so that the ventilation bore leads into the collecting chamber. The collecting chamber rests form-fittingly and sealingly on the surface area of the emergency opening cylinder. The collecting chamber may, for example, have a U-shaped cross-section and a ring-shaped construction. Such a ring-shaped, collar-shaped collecting chamber may be pushed in the axial direction onto the surface area of the emergency opening cylinder and cover the area of the ventilation bore. A controllable outlet valve, which is connected with a control, is arranged in the wall of the collecting chamber. The outlet valve closes and opens the valve duct between the collecting chamber and the outer atmosphere. The outlet valve is closed and, with the passing of the ventilation bore by the piston head, a control opens the outlet valve only after a time delay or after the completion of a subsequent piston travel.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompany drawings.
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Blum Stefan
Nickl Thomas
Spellmeier Wolfgang
Barefoot Galen L.
Crowell & Moring LLP
Eurocopter Deutschland GmbH
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