Abstract:
A flight data recorder having a crash survivable memory unit, a processing unit, a data transmit device and a support device for supporting the data transmit device. The support device includes an electromagnetic interference reduction device that surrounds the data transmit device. The support device is coupled to the crash survivable memory unit or the processing unit for supporting the electromagnetic interference reduction device.

Description:
BACKGROUND  
       [0001]     A flight data recorder used on military helicopter includes an exposed flexible circuit portion. The exposed flexible circuit portion emits an unacceptably high level of electromagnetic radiation. In order to reduce the emission of electromagnetic radiation, ferrite core is applied to surround flexible circuit and to attenuate the emission. However, in the high vibration environment of a helicopter, the combination of the ferrite core and the flexible circuit deteriorates and results in premature failure.  
         [0002]     Therefore, there exists a need for a mechanism for stemming the life of a flexible circuit used in data recorders for helicopters. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0003]     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.  
         [0004]      FIG. 1  is a perspective view of a flight data recorder formed in accordance with an embodiment of the present invention;  
         [0005]      FIG. 2  is a partial front view of the flight data recorder shown in  FIG. 1 ;  
         [0006]      FIG. 3  illustrates a partial x-ray side view of the flight data recorder shown in  FIG. 1 ; and  
         [0007]      FIG. 4  illustrates a front view of a component of the flight data recorder. 
     
    
     DETAILED DESCRIPTION  
       [0008]      FIG. 1  illustrates a perspective view of a flight data recorder  20  formed in accordance with an embodiment of the present invention. The flight data recorder  20  includes a crash-survivable memory unit  22  and a processing unit  24 . The flight data recorder  20  also includes a data transfer and support device  30 , which will be described in more detail below.  
         [0009]      FIG. 2  illustrates a partial side view of the flight data recorder  20 . The data transfer and support device  30  includes a flexprint circuit  40  that is connected to internal circuitry of the processing unit  24  and memory storage devices within the crash-survivable memory unit  22 . In this embodiment, the data transfer and support device  30  includes a ferrite core  42  and a support bridge  48  and a flexprint circuit connector  56 . The ferrite core  42  includes first and second sections  44  and  46 . The support bridge  48  includes first and second sections  50  and  52  The flexprint circuit connector  56  connects the flexprint circuit  40  to the internal circuitry of the processing unit  24 .  FIG. 3  shows the flexprint circuit connector  56  connected to components within the processing unit  24 .  
         [0010]     As shown in  FIG. 4 , the first and second sections of the ferrite core  44  and  46  attach at ends to form a complete ring around the flexprint circuit  40 . Isolator pads  70  and  72  are positioned between the ferrite core sections  44  and  46  and the flexprint circuit  40 . Example isolator pads  70  and  72  are silicon cushions, such as those produced by Nott Atwater Company (e.g., mil. spec. no. 600-6108-002). In one embodiment, the isolator pads  70  and  72  include an adhesive on one side for attaching to respective inside surfaces of the ferrite core sections  44  and  46 .  
         [0011]     The first and second sections  50  and  52  of the support bridge  48  combine to form a ring that securely holds the ferrite core sections  44  and  46 . Adhesive  76  is applied between the ferrite core sections  44  and  46  and inner surfaces of the support bridge sections  50  and  52 . The Adhesive  76  ensures that the ferrite core sections  44  and  46  are securely held within the support bridge sections  50  and  52 . Attachment devices  80 , such as screws, bolts, rivets or other securing devices are applied through cavities at ends of the support bridge sections  50  and  52  and through cavities at ends of the flexprint connector  56  and are received by a receiving device  84  ( FIG. 3 ) located within the processing unit  24 , thereby causing the sections of the support bridge sections  50  and  52  and the flexprint circuit connector  56  to be held securely against the surface of the processing unit  24 . In one embodiment, the receiving device  84  is a nut plate.  
         [0012]     The support bridge  48  is positioned in order to locate the ferrite core  42  to receive the flexprint circuit  30  such that the flexprint circuit  30  is received by the flexprint circuit connector  56  and by a receiving cavity (not shown) of the crash-survivable memory unit  22  without any undue bending. The support bridge  48  is positioned to greatly reduce the amount of vibration experienced by the flexprint circuit  30 .  
         [0013]     In one embodiment, the support bridge sections  50  and  52  are formed of plastic, such as Delrin, an easily machined vibration damping plastic that is stable over a wide range of temperatures, or comparable lightweight durable low wear, low friction material. In one embodiment, the adhesive  76  is a double-sided tape, such as that produced by 3M.  
         [0014]     When the data transmit and support device  30  is fully formed and secured to the processing unit  24 , the ferrite core sections  44  and  46  are securely held together thereby presenting a contiguous ferrite core surface around the flexprint circuit  40 , thus reducing electromagnetic interference of data transmitted from processing unit  24  to the crash-survivable memory unit  22  over the flexprint circuit  40 .  
         [0015]     While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.