Abstract:
The self closing aircraft door includes two overlapping door panels and is attached to an outer skin of the aircraft by a plurality of suction cups. Each of the door panels comprises a net material at least partially surrounded by a flexible frame. Each of the panels also includes essentially parallel connecting rods comprising a plurality of magnetic and non-magnetic segments. The door is structured so that in the closed position, the magnetic segments in the connecting rods of the two panels join and thereby create a physical barrier to insects which might otherwise enter the aircraft cabin.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/779,622 filed Mar. 13, 2013, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The disclosed apparatus relates to a self closing door for aircraft. Specifically, the apparatus described herein relates to a net door designed to fit on the convex outer surface of an aircraft and thereby prevent the entry of insects into the cabin of the aircraft. 
     BACKGROUND OF THE INVENTION 
     As the number of (particularly international) flights increase, there is a corresponding increase in the danger of contaminating vulnerable human and agricultural environments with invasive insects. Invasive insects can have devastating consequences for the agricultural production of the affected environments. For example, the brown marmorated stink bug ( Halyomorpha halys ) continues to cause considerable damage to United States (US) East Coast apple, peach, and grape crops. For example, apple growers in the US Mid-Atlantic region reported nearly $40 million in crop damage from the insect. 
     Other invasive insects spread disease among humans and animals. For example, a variety of mosquitoes spread a wide range of dangerous diseases including malaria, dengue fever, west nile virus, and yellow fever. International air travel is thought to be one reason why the Asian tiger mosquito ( Aedes albopictus ) has become so firmly established on the US East Coast and in many non-native locations around the world. 
     The airline industry, in general, has been slow to address the problem. Some airlines apply a variety of aerosol insecticides to try to “disinsect” aircraft interiors. Airlines also have entire aircraft treated at regular intervals with contact residual insecticides, including seats and carpets in passenger cabins. However, the use of insecticides is problematic because some members of the public are sensitive to the chemicals used in the insecticides. The problem is compounded because the chemical odor associated with the aerosols detracts from the otherwise desirable environment inside the cabin and further exacerbates the problem of public sensitivity, particularly among senior citizens, infants, and the immunocompromised. Flight crews who repeatedly spend extended amounts of time in the aircraft are also impacted and may suffer negative effects from exposure to the chemicals in the insecticides. 
     There is also some use of “air curtain” equipment, which prevents entry of insects into aircraft while passengers are embarking or disembarking. Any insects attempting to fly into the aircraft must overcome the substantial machine-generated air flow across the aircraft cabin door used for passenger entry. 
     Although the “air curtain” provides some contamination protection, the air curtain cannot provide an actually physical barrier, and installation of air curtain machinery for all aircraft doors may not be possible or practical. Further, the non-uniform design of aircraft doorways may negatively impact the effectiveness of some air curtain machinery. 
     The need exists for a means of minimizing the vulnerability of aircraft cabins to contamination by damaging and disease-causing insects, particularly while aircraft are on the ground with cabin doors open. The apparatus described herein comprises a self closing door that attaches easily to the exterior of essentially all aircraft and provides a physical barrier to the entry of insects into the cabin. The current door apparatus is inexpensive and versatile, and can be used either alone, or in combination with current conventional insect exclusion techniques and devices. 
     SUMMARY OF THE INVENTION 
     This disclosure is directed to a self closing aircraft door comprising essentially mirror image first and second door panels. Each of the door panels comprises a net screening material surrounded by a flexible frame. A plurality of suction cups are attached to and positioned along at least one side of the net material or flexible frame. A pair of essentially parallel connecting rods is also positioned along one side of the net material or flexible frame. Each one of the connecting rods comprises magnetic and non-magnetic segments. 
     The door is structured so that as the suction cups hold the first and the second door panels to the aircraft, the magnetic segments in the two parallel connecting rods in the first door panel, connect with the magnetic segments in the two parallel connecting rods in second door panel, to thereby create the self closing aircraft door apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a single panel of the self closing door. 
         FIG. 2  is a view of the two panels that comprise the self closing door. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As generally shown in  FIGS. 1 and 2 , the self closing door apparatus  10  comprises a first panel  12  and a mirror-image second panel  14 . 
     As best shown in  FIG. 1 , in the preferred embodiment, the first panel  12  includes a 4-6 inch flexible vinyl frame  16  that has a generally rectangular shape. The frame  16  surrounds a heavy weight mosquito net-type mesh  18 , with a 2-inch webbing. The webbing is sewn into the vinyl frame  16  to create a durable and flexible panel  12 . 
     In alternative embodiments, the door apparatus  10  and individual panels  12  and  14  can have a variety of shapes, as required by the type of aircraft door way in which the apparatus  10  will be applied. The frame  16  can be comprised of a variety of flexible, semi-flexible, and rigid materials consistent with the function of providing a door-type barrier to be positioned on a convex aircraft skin. In at least one embodiment, the outer edge of the net  18  may (or may not) comprise the frame  16 . The net  18  may be comprised of a variety of materials including cloth, wire, plastic and composite materials. The material comprising the net  18  may also comprise insecticide-impregnated fibers. 
     As generally shown in  FIGS. 1 and 2 , the frame  16  may further comprise a plurality of aircraft skin attachment devices  20  specifically designed to adhere the panels  12 ,  14  to the skin of the aircraft. In the preferred embodiment, the attachment devices  20  may comprise suction cups  20  designed to adhere to aluminum or composite aircraft skin. The spacing and specific configuration of the suction cups  20  is generally a function of the size of the individual panels  12 ,  14  and the nature of the aircraft skin. 
     The design of the panel connection devices  20  is particularly critical, inventive, and non-obvious for a variety of reasons. It is crucial that the connection devices  20  attach to the outer skin of the aircraft and create a strong but non-abrasive bond. The aircraft skin is comprised of a non-magnetic convex surface that is somewhat vulnerable to abrasion. Even small abrasions to the skin of the aircraft may provide an avenue for corrosion and cabin pressure (air) leaks as well as the entry of moisture into sensitive electrical and/or hydraulic component areas. 
     Clamps or other mechanical connectors can damage the aircraft skin. A variety of connection mechanisms such as eyelets, sockets, cleats and the like could effectively secure the door, but these connectors require special modification of the aircraft skin and may detrimentally affect aircraft aerodynamics. Some chemical adhesives may be effective and non-abrasive, but removal can damage aircraft paint and can be ineffective if the aircraft skin is dusty or wet. 
     The design of the door attachment devices  20  disclosed herein enables the panels  12 ,  14  to be quickly and easily installed or removed from a wide variety of aircraft hulls, by a single person, without special tools or training, and in inclement weather conditions. The combination of the flexible door apparatus  10 , and the suction cup design of the door attachment devices  20  comprises a significant and non-obvious contribution to the art. 
     As best shown in  FIG. 1 , the edge of the panel frame  16  opposite the aircraft skin attachment devices  20  comprises the self closing assembly  22 . The self closing assembly  22  comprises two essentially identical parallel elongated connecting rods  24 . Each of the connecting rods  24  comprises alternating sections of magnet  26  and rigid (preferably fiberglass) cylinders  28 . In the preferred embodiment, the rods  24  are essentially semi-rigid and unitary, and the magnets comprise neodymium magnets. 
     Significantly, when the door attachment devices  20  are connected to the host aircraft skin, the panels  12   14  (in combination with the flexible rods  24 ) are bowed outwardly and formed into a convex shape that mimics and conforms to the shape of the host aircraft body. Specifically, the reversibly flexible (i.e. elastically bendable) nature and construction of the door frame  16  and the connecting rods  24  enables the apparatus  10  to accommodate a wide variety of aircraft fuselage configurations without permanent modification to the apparatus  10  components. This is a somewhat unexpected (and advantageous) result that improves the performance of the door apparatus  10 . The convex shape of the door causes the bottom portion of the panels  12 ,  14  to form a better closure/seal with the bottom of the aircraft door opening. In prior art net doors which vertically hang straight down, at least a portion of the cabin floor adjacent to the aircraft doorway is exposed. This exposed gap creates a space where small insects (such as fruit flies, beetles, and mosquitoes) can be concealed and go undetected in the carpet and crevices adjacent to the door. 
     In alternative embodiments, the rods  24  may be comprised of materials other than fiberglass. The magnets  26  may be comprised of any magnetic material known in the art. Further, magnets  26  may be present only on one side of a panel (for example 12) at a designated position, while the corresponding panel (for example 14) position may comprise an attractive material (such as steel or iron) that may not be a (conventional) magnet. In the preferred and alternative embodiments the rods  24  and rod sections  26 ,  28  may have a cylindrical or non-cylindrical cross-sectional shape. 
     Although some prior art net doors include magnet closure devices, the prior art doors lack the double-fiberglass rod design or the suction cup attachment devices  20 . The structure of the parallel fiberglass rods  28  (in combination with the magnets  26 ) results in a more stable door apparatus  10  that is less likely to gap open, and is more durable and effective than current conventional net doors. The fiberglass rods  28  also re-enforce and facilitate the vertical alignment of the magnets  26  on opposing door panels  12 ,  14 , and ensure to ensure better closure/seal with the bottom portion of the aircraft door. Merely adding another row of magnets to an existing conventional net door does not achieve the same consistency of operational performance as the apparatus  10  described herein. Further, as discussed supra, the flexibility of the door components enables the door panels  12 ,  14  to conform to a wide variety of aircraft fuselage outer contours. 
     In operation, as best shown in  FIG. 2 , the door apparatus  10  is positioned in the doorway of an aircraft so that a first panel  12  is on one side of the aircraft doorway, and a second panel  14  is on the opposite side of the doorway. The door apparatus  10  is positioned so that suction cups  20  ( FIG. 1 ) adhere to the outer convex skin of the aircraft, and thereby hold the apparatus  10  in position on the aircraft. The panels  12 ,  14  are positioned so that the areas designated by the dashed line  30  form an overlap area ( FIG. 2 ). In the overlapping area  30 , the connecting rod  24  magnets  26  ( FIG. 1 ) on each of the panels  12 ,  14  adhere to corresponding magnets  26  on the opposite panel  12 ,  14 , so that the magnets  26  in combination with fiberglass supporting segments  28  form the self-closing portion  22  of door apparatus  10  ( FIG. 1 ). 
     As personnel approach the aircraft doorway, they part the panels  12 ,  14  and proceed through the door apparatus  10  and into or out of the cabin. After they move away from the aircraft door area and break contact with the apparatus  10 , the self closing portion  22  of the apparatus  10  causes the magnets  26  on the panels  12 ,  14  to rejoin and thereby re-close the door  10 . 
     For the foregoing reasons, it is clear that the apparatus described herein provides an innovative, and versatile self closing net aircraft door. The current system may be modified in multiple ways and applied in various technological applications. The disclosed method and apparatus may be modified and customized as required by a specific operation or application, and the individual components may be modified and defined, as required, to achieve the desired result. 
     Although some of the materials of construction are not described, they may include a variety of compositions consistent with the function described herein. Such variations are not to be regarded as a departure from the spirit and scope of this disclosure, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.