Abstract:
A mounting device for mounting electronic components of an unmanned helicopter. A solid base plate has a circumferential outer edge. A connecting module is fixedly attached to the circumferential outer edge. The connecting module is configured to reversibly connect a flexible cover to the base plate.

Description:
[0001]    The present invention relates to mounting devices for electronic components of unmanned areal vehicle (UAV) helicopters. Mounting devices of the invention comprise a solid base plate and a flexible cover connected to the base plate. The present invention also relates to UAV helicopters comprising such mounting devices and to methods of mounting electronic components to UAV helicopters using the mounting devices. 
       BACKGROUND OF THE INVENTION 
       [0002]    Unmanned aerial vehicle (UAV) helicopters are employed mainly for exploration purposes. UAV helicopters are often operated from naval ships. When helicopters enter the marine environment, e.g., from a naval aircraft carrier, the electronic components get exposed to harsh weather conditions (e.g. moist, salt, wind). Therefore it is an object of present invention to protect the electronic components from these conditions by mounting the electronic components on mounting devices comprising a light, flexible cover. 
         [0003]    The electronic components of UAV helicopters are often distributed over the entire aircraft. In order to protect these electronic components from the harsh environmental conditions, the components are often individually protected by mostly solid covers. This is cumbersome, costly and adds additional weight to the helicopter. 
         [0004]    Since the helicopter is to be kept as light-weight as possible, conventional protection means, e.g., rigid covers or boxes provided for the individual electronic components are often not appropriate. Total weight of the multiple covers is too high. Furthermore, rigid covers tend to be sensitive to strong vibrations, since this produces heavy mechanical stress. As a result of the heavy mechanical stress, rigid covers often become leaky, or break. 
         [0005]    The above problems are solved by the present invention by arranging a major portion of the electronic components of the helicopter on a single mounting device, and covering the mounted electronic components by a single, light-weight, flexible cover. 
         [0006]    Flexible covers for protection of electronic components are known in the art. 
         [0007]    U.S. Pat. No. 5,545,494 describes an environmental protector for electronic devices in outside terminal boxes. The protector comprises a laminate cover which provides a moisture barrier, penetration resistant surface and EMI shield. The protector may be flexible or substantially rigid and is in the form of an open-ended container for receiving an electronics device. The container is sealed at the open end around a connector unit. U.S. Pat. No. 5,545,494 does not disclose connecting means for reversibly connecting the cover to the base plate. 
         [0008]    JP 2003055806 A discloses the protection of electronic components, such as mp3 players, cellular phones, and personal digital assistants (PDAs) by a flexible bag or cloth comprising a water repellent fabric, a waterproof fabric, a moisture permeable waterproof fabric, a moisture absorbing fabric, a pH adjustment fabric, an anti-electric fabric or a shock absorbing fabric. 
         [0009]    In view of the above stated prior art, it is an object of the present invention to provide an improved mounting device for the electronic components of UAV helicopters, which mounting device provides for convenient mounting of the electronic components and furthermore provide for a light-weight overall construction. The improved mounting devices are also to provide tolerance against strong vibrations and mechanical stress. It is a further object of the invention to provide an improved mounting device which is simple and easy to install. 
       SUMMARY OF THE INVENTION 
       [0010]    The above objects are achieved by providing an improved mounting device for mounting electronic components of an unmanned helicopter comprising a solid base plate having a circumferential outer edge, and connecting means fixedly attached to said circumferential, outer edge for reversibly connecting a flexible cover to said base plate. 
         [0011]    “Electronic components”, according to the invention, shall be understood to be any electronic components used on a UAV helicopter, such as, e.g., helicopter&#39;s central control system. 
         [0012]    The circumferential outer edge shall be understood as being the peripheral part of the base plate. It preferably extends 0.5, 1, 2, 4, 10 cm inwards from the peripheral end of the base plate. 
         [0013]    The solid base plate is preferably a metal base plate, such as, e.g., an aluminum base plate, or a plate manufactured from another light-weight metal alloy. The material has preferably good heat conducting properties of above 10, 20, 40, 80, 100, 150, 200 Watts per meter and degree Kelvin. 
         [0014]    In a preferred embodiment of the invention, the mounting device, and/or its base plate is substantially saddle-shaped. A saddle shaped mounting device and/or base plate allows compact placement of the electronic components in a rear part of the fuselage, e.g., on (or around) a tail section of the helicopter. The base plate is thus preferably adapted to be mounted on a tail section of the unmanned helicopter. 
         [0015]    In another preferred embodiment of the invention, the base plate further comprises an interface plate for providing electrical contacts to peripheral electrical components or instruments. These contacts are preferably adapted to harsh weather conditions, e.g., they comprise waterproof electrical contacts (plugs and/or sockets). 
         [0016]    In another preferred embodiment of the invention, said base plate comprises, when mounted on a helicopter, a substantially horizontal part and two substantially vertical parts. Each of said vertical parts may be connected to said horizontal part at opposite sides thereof. Such construction yields the desired “saddle-shaped” base plate, which can conveniently be mounted on a tail section of the helicopter, e.g., in a rear part of the fuselage of the helicopter. 
         [0017]    Preferably, the base plate comprises cooling ribs. The cooling ribs are preferably provided on the side opposite from the side on which the electronic components are mounted. The electronic components are preferably mounted on only one side of the base plate. 
         [0018]    In a further preferred embodiment, the base plate comprises vibration damping means. This serves to protect the base plate and the electronic components from strong vibrations of the tail of the helicopter, to which the mounting device is mounted. Damping means may be mechanical or elastic damping means. Damping means may also be hydraulic damping means or a combination of mechanical and hydraulic damping means. 
         [0019]    In a further preferred embodiment, the connecting means is fixedly attached to said base plate along the entire circumferential outer edge. This provides for an efficient seal between the base plate and the flexible cover around the entire circumferential edge of the base plate. The seal is preferably a water-tight or an air-tight seal. 
         [0020]    In a further preferred embodiment, the connecting means comprises a connector selected from the group consisting of zipper connector, e.g., re-sealable zipper connector, or water-tight zipper connector, a zip-lock connector, a snap button connector, and a hook-and-loop fastener connector. These connectors, all known per se, provide for a convenient reversible connection of the flexible cover and the base plate. In a preferred embodiment, the connecting means comprises an interlocking groove and ridge that form a tight seal when pressed together. This type of connection is used in e.g. zip-lock connectors. 
         [0021]    A “zipper”, according to the invention, is a device for temporarily joining two edges of fabric or flexible material, as it is commonly used in clothing (e.g. jackets and jeans), luggage, sporting goods, camping gear (e.g., tents and sleeping bags), and other daily use items. 
         [0022]    In one embodiment, one of said interlocking groove and ridge is directly attached to said circumferential outer edge (without intermediate connecting materials between said groove or ridge and the base plate). The other one of said interlocking groove and ridge is fixedly attached to the flexible cover. This allows for easy connection of the flexible cover to the base plate. 
         [0023]    Alternatively, said connecting means may comprise a flexible connecting sheet (or band), fixedly attached to said base plate at a first side of said connecting sheet, and a connector being provided on an opposing second side of the connecting sheet (or band). This embodiment is particularly preferred, if the connector is a zipper-type connector. The sheet may be 1, 2, 4, 10 cm in breadth. 
         [0024]    Preferably, the flexible cover is waterproof. In some instances, it is advantageous if said flexible cover is breathable. In another preferred embodiment the flexible cover is heat resistant. A cover is heat resistant, according to the invention, if it can withstand temperatures of more than 45, 100, 200, 400, 800, or preferably 1600 degrees Celsius. Preferred flexible covers are elastic. The cover may be transparent. 
         [0025]    Preferably, the flexible cover has a breathability (resistance to the diffusion of water vapor, measured in s/m) of less than 2000, preferably less than 1000, 800, 600, 500, 400 m/s at a mean relative humidity of 0.5, as measured by the method of Gibson (Gibson et al., Convection/Diffusion Test Method for Porous Textiles, International Journal of Clothing Science and Technology 12 (2), 2000). 
         [0026]    For a fabric to be classified as waterproof it needs to withstand water pressure applied from a 1 meter high column, and not leak. Flexible covers of the invention preferably withstand water pressure applied by a 10, 20, 40, 60 or 100 cm high water column without leaking. 
         [0027]    The flexible cover may comprise a textile fabric cover, a breathable textile fabric cover, a breathable polymer sheet, a breathable membrane sandwiched between textile sheets, a flexible PVC cover, a thermoplastic polymer cover. The flexible cover may comprise multiple layers of flexible material. It may also comprise a metal foil or film. Preferably said flexible cover comprises a layer conferring protection against electromagnetic radiation, such as an electromagnetic induction (EMI) protection layer. 
         [0028]    In one embodiment, said flexible cover comprises a closable opening for allowing access to electronic components underneath the cover. The closable opening, when closed, preferably provides a waterproof (or air-tight) seal. 
         [0000]    It is furthermore preferred that the cover is provided with a closable valve for releasing air from beneath the cover. The valve may also be used to actively withdraw air from beneath the cover, which results in a more compact package. 
         [0029]    The flexible cover may also comprise a water drain, such as a valve or water absorption means. The water drain may be a valve for releasing water from underneath the cover, or may comprise absorption means such as a sponge or a hygroscopic material. 
         [0030]    In preferred mounting devices, the electronic components are sealed between the base plate and the flexible cover, preferably by means of an air-tight seal or a waterproof seal. 
         [0031]    The present invention furthermore relates to the above described mounting devices, wherein said mounting devices further comprise said flexible cover, i.e., the (still removable) cover forms part of the mounting device. 
         [0032]    The present invention further relates to an unmanned helicopter comprising a mounting device as described above. Preferably, the unmanned helicopter comprises mounting device as described above, and the mounting device is mounted beneath an outer body panel of the helicopter&#39;s fuselage. 
         [0033]    The present invention further relates to a method of mounting electronic components on a UAV helicopter, said method comprising, in any order, mounting said electronic components on a mounting device as described above; sealing said electronic components between the base plate of the mounting device and the flexible cover (e.g. by closing the connector means); and mounting said mounting device to the UAV helicopter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  shows a UAV helicopter of the invention. 
           [0035]      FIG. 2  shows a mounting device of the invention, with electronic components and a flexible cover. 
           [0036]      FIG. 3  shows a mounting device of the invention without the flexible cover. 
           [0037]      FIG. 4  shows a mounting device of the invention with the flexible cover of the invention. 
           [0038]      FIG. 5  shows connecting means of the invention, comprising a flexible connecting sheet fixedly attached to the base plate. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    The present invention relates to mounting devices  1  for mounting the electronic components of helicopters at a central place within the aircraft. The invention relates further to flexible covers  5  for protecting the electronic components mounted on mounting devices of the invention from environmental factors, such as wind, salt and extreme temperatures. 
         [0040]    As can best be seen in  FIGS. 3 and 4 , mounting device  1  comprises a solid base plate  2 , preferably made of light-weight material, such as aluminum or another light-weight metal alloy. One important feature of the base plate  2  is that it has good thermal conductivity. In the embodiments shown in  FIGS. 2 ,  3  and  4 , base plate  2  essentially comprises four parts, a substantially horizontal part  21 , two substantially vertical parts  13 ,  13 ′ and an interface plate  12 . The horizontal part is preferably milled out of a single block of aluminum. At each of its longer sides one of the vertical parts  13 ,  13 ′ is attached. The attachment of the vertical parts  13 ,  13 ′ may be a sealed connection. An interface plate  12  is connected to one of the vertical parts  13 ,  13 ′, which comprises socket means  14  for connection to corresponding plug means of peripheral electrical devices. These socket means  14  provide an external access to the electronic components under flexible cover  5 . All socket means  14  are sealed. Socket means  14  are preferably waterproof sockets. 
         [0041]    As can best be seen in  FIG. 1 , the mounting device  1  with electronic components and the flexible cover  5  are mounted under, and covered by, the body panels ( 19 ) forming the helicopter&#39;s fuselage. 
         [0042]    Base plate  2  has a circumferential outer edge  3 . The circumferential outer edge  3  is preferably rounded off and/or chamfered, in order to avoid any damage to the flexible cover by sharp edges. 
         [0043]    As can best be seen in  FIG. 5 , connecting means  4  is fixedly attached to the circumferential outer edge  3 , for connecting a flexible cover  5  to the base plate  2 . Connecting means  4  comprises a flexible connecting sheet  20  fixedly attached to the base plate  2  along the circumferential outer edge  3 . Flexible connecting sheet (or band)  20  can be glued to the base plate  2 , or be attached thereto with screws, nuts or bolts. Quick fasteners, such as bayonet joints are also contemplated. Connecting means  4  further comprises connector  6  that provide for the reversible attachment of flexible cover  5  to the flexible connecting sheet  20 . Preferred connectors are zippers. The connection between connecting means  4  and base plate  2  is preferably sealed, or an otherwise air-tight and/or waterproof connection. 
         [0044]    If the connector  6  is a zipper, then one part of the connector is preferably attached to the flexible connection sheet, while the other part is attached to the flexible cover  5 . In another embodiment, connector  6  is directly attached to the base plate  2 , e.g., when using snap fasteners, hook-and-loop fasteners, or zip-lock type connections. 
         [0045]    All connectors  6  preferably provide a water-tight, air-tight releasable connection. 
         [0046]    When a zipper is used, one part of the zipper may be glued to base plate  2  along the circumferential outer edge of the base plate. The other half of the zipper is fixedly connected, e.g., sawn and sealed, to the edge of the flexible cover  5 . 
         [0047]    In order to transfer heat generated by the electronic components mounted on the base plate  2 , cooling ribs (or flanges)  8  are provided on the bottom side of base plate  2 . Cooling may further be supported by airflow through channels in the fuselage body of the helicopter. 
         [0048]    The cooling ribs  8  are preferably monolithically milled out of the same aluminum block as base plate  2 . Alternatively, the cooling ribs  8  may be separately mounted on the bottom side of the base plate. A fan may be incorporated to provide for even more efficient cooling of the base plate  2 . 
         [0049]    In an alternative embodiment, base plate  2  comprises a rig for mounting a heat pipe and/or a water cooling pipeline. 
         [0050]    The flexible cover  5  may provide protection against electromagnetic interferences (EMI). In this case, connection means and seals are conductive to prevent electrical arcing, static sparks, and the overall build-up of charge within rubber that may cause it to behave like a capacitor. 
         [0051]    Base plate  2  is connected to the helicopter through damping means  9 . This is to dampen the oscillations/vibrations caused by the main rotor and the engine. The damping means  9  shown in  FIG. 4  comprise mechanical damping means, e.g., rubber plates or springs. The damping means  9  are connected to the fuselage of the helicopter by screws, but other ways of mounting may be conceivable, such as bayonet joints, or quick fasteners. 
         [0052]    Flexible cover  5  shown in  FIGS. 2 and 4  is preferably made out of textile fabric. The cover may comprise a waterproof yet breathable membrane. The textile fabric may comprise thermoplastic fibers, aramid fibers (e.g. Twaron) which have flame-retardant, cut-protection and armor characteristics. Other fibers for the cover  5  may be acrylic fibers, nylon fibers, polyurethane fibers, hydrophobic olefin fibers, polylactide fibers or metallic fibers, such as Lurex. Another possible textile fabric is Gore-Tex, which is a waterproof and breathable fabric. Flexible cover  5  may also be a Latex cover or other natural and/or synthetic materials that offer same characteristics as Latex. 
         [0053]    Since there is normally air entrapped under the flexible cover  5 , the expansion of the enclosed air at decreasing pressures (high altitudes) has to be considered. Therefore, in one preferred embodiment, the flexible cover  5  is breathable. The breathable cover allows air to pass through the cover for pressure adjustment. In extreme cases, this will help to avoid explosion of the cover. Alternatively, pressure adjustment valves or strong flexible cover materials can be used. 
         [0054]    As can be seen in  FIGS. 1 and 4 , flexible cover  5  fits tightly around the electronic components mounted on the base plate  2 . 
         [0055]    As shown in  FIG. 4 , flexible cover  5  may include an opening  11  for allowing access to the electronic components beneath flexible cover  5 . This opening gives access to a specific area under the flexible cover  5 , e.g., for maintenance purposes. Preferably, opening  11  is re-closable. The re-closable opening  11  to may comprise the same type of reversible connection means as connecting means  4  for the attachment of the flexible cover  5  to the base plate  2 . 
         [0056]    The mounting device  1  preferably comprises water drain means, such as water drain channels or water traps on the inside of the flexible cover  5 . It may also comprise water drain valves to eliminate accumulated water beneath the cover. 
         [0057]    In alternative embodiments, the water drain means comprise water absorbent means, e.g., a sponge or a hygroscopic material. 
         [0058]    Another possibility of preventing condensation of water is the incorporation of a valve for connecting a vacuum pump to withdraw air, potentially humid air, from within the flexible cover  5 . The flexible cover  5  may also have a water drain valve and/or an air-exhaustion valve for a vacuum pump combined within one and the same device. 
         [0059]    As can be seen in  FIGS. 1 to 4 , base plate  2  assumes the shape of a horse saddle. This saddle-shaped construction allows convenient mounting on the mounting device, e.g., on and partly around a tail section of the helicopter, preferably at a rear part of the fuselage (see  FIG. 1 ). The placement of the main electronic components of the helicopter at one central place within the helicopter, on a single base plate  2  allows easy maintenance and/or replacement of the electronic components.