Abstract:
Reception coupling unit of a hose and drogue device of a tanker aircraft with the probe of a receiver aircraft for in-flight refueling, including, respectively, first and second cooperating latching devices that can be positioned in one or more latching states in a refueling operation, in which the reception coupling unit includes at least a detector of the latching states and at least a first indication device and/or a second indication device for providing, respectively, to the pilot of the receiver aircraft and/or to the crew of the tanker aircraft indications that the cooperating latching devices are positioned in one or more of the latching states, the detector being operatively connected, respectively, to a first indication device and/or to a second indication device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of European Patent Application 11382398.3, filed on Dec. 23, 2011, the entire contents of which is incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to aircraft refueling hoses and more specifically to the latching system that ensures the connection to the probe to the reception coupling unit of the hose. 
         [0004]    2. Background 
         [0005]    One method for in-flight refueling operations is based on the use of a hose and drogue device that makes contact with a probe of the receiver aircraft allowing fuel to pass from the tanker aircraft to the receiver aircraft. 
         [0006]    The drogue is used to stabilize the hose trailing from a fuel tanker aircraft. It also provides the drag to maintain the hose catenary and the mating force with a probe from a receiver aircraft to be refueled. The drogue is attached to a reception coupling unit at the end of the hose, which has a passage for receiving the probe nozzle, and supports a canopy or parachute surrounding the passage opening and providing drag for the coupling unit. 
         [0007]    The hose and drogue device may have illumination means as those disclosed in US 2009/0302161 to assist the receiver pilot to align the probe with the drogue and reception coupling passage in low light or darkness. 
         [0008]    The connection between the probe and the reception coupling unit of the hose shall be ensured by a latching system. 
         [0009]    U.S. Pat. No. 2,692,102 and U.S. Pat. No. 3,059,895 disclose a latching system based on some rollers which run on the receiver probe and which are allocated on a circumferential groove of the receiver probe when the full contact is performed. Those rollers are kept pressed against the receiver probe by spring-plunger assemblies. 
         [0010]    This latching system has the disadvantage that the connection between the probe and the hose reception coupling unit can be kept in an intermediate latching state, where the latching system is not in its locking position. At those conditions, the refueling operation can be performed with relative movements between the hose reception coupling unit and the receiver probe. 
         [0011]    The present invention is focused to the solution of this problem. 
       SUMMARY OF THE INVENTION 
       [0012]    It is an object of the present invention to provide a latching system for in-flight refueling operations between a tanker aircraft and a receiver aircraft using a hose and drogue device that assures that the refueling operation is performed without relative movements between the tanker reception coupling unit and the receiver probe. 
         [0013]    In one aspect, this and other objects are met by a reception coupling unit of a hose and drogue device of a tanker aircraft with the probe of a receiver aircraft for in-flight refueling, the reception coupling unit and the probe comprising, respectively, first and second cooperating latching means that can be positioned in a non-latched state, in an intermediate latching state and in a latched state during a refueling operation, the reception coupling unit comprising at least a detector of said latching states and at least a first indication means and/or a second indication means for providing, respectively, to the pilot of the receiver aircraft and/or to the crew of the tanker aircraft indications that said cooperating latching means are positioned in one or more of said latching states, said detector being operatively connected, respectively, to a first indication means and/or to a second indication means. 
         [0014]    In one embodiment, said second cooperating means is a circumferential groove in the probe and said first cooperating means comprises at least a roller arranged in the reception coupling unit for running over the incoming probe, then being said latching means in an intermediate latching state, until the roller is allocated on said circumferential groove, then being said latching means in a latched state. Therefore latching detection means operatively connected to the indication means for the pilot of the receiver aircraft and/or to the crew of the tanker aircraft are incorporated to known latching systems allowing the pilot of the receiver aircraft and/or the crew of the tanker aircraft to take the required corrective actions that lead to a proper connection. 
         [0015]    In one embodiment, the reception coupling unit comprises a detector for said roller which is operatively connected to a first indication means and/or to a second indication means for activating said indication means when the roller is positioned in said intermediate latching state. Where the detector may be a position detector, such as an optical sensing element or a mechanical sensing element capable of detecting the position of the roller in the intermediate latching state. 
         [0016]    In one embodiment, said first indication means is a light source, preferably a Light Emitting Diode (LED) device, arranged in the external surface of the reception coupling unit connected to an electric circuit having a switch for turning ON/OFF said light source which is controlled by said detector which closes the circuit when the roller is in an intermediate latching state and opens the circuit otherwise. Therefore, a visual indication means of the intermediate latching state for the pilot of the receiver aircraft is provided. 
         [0017]    In one embodiment, said electric circuit comprises a flasher component so that said light source will emit a flashing light when the electric circuit is closed. 
         [0018]    In one embodiment, said second indication means is a signal emitter, it maybe be a radio emitter or a micro-wave radio emitter, connected to an electric circuit having a switch for turning ON/OFF said signal emitter which is controlled by said detector. An indication means, which may be an acoustic indication means, of the intermediate latching state for the crew of the tanker aircraft is provided. 
         [0019]    In one embodiment, said electric circuit comprises an air-driven generator and a backup battery as electrical energy sources. 
         [0020]    In one embodiment said first indication means is a sliding pin between recessed and protruding positions with respect to the external surface of the reception coupling unit connected to a mechanical detector arranged to move the sliding pin to the protruding position when said roller is in an intermediate latching state and to the recessed position otherwise. A visual indication means of the intermediate latching state for the pilot of the receiver aircraft is provided. 
         [0021]    In one embodiment said mechanical detector is an assembly of a cam and a lever arranged for interacting with said roller to move the sliding pin to the protruding position in an intermediate latching state, so that it can be seen by the receptor pilot, and to the recessed position otherwise. 
         [0022]    Other characteristics and advantages of the present invention will be clear from the following detailed description of embodiments illustrative of its object in relation to the attached figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a schematic view of a refueling operation between a tanker aircraft and a receiver aircraft using a hose and drogue device. 
           [0024]      FIG. 2  is a cross section view of the reception coupling unit of a hose and drogue device. 
           [0025]      FIGS. 3   a ,  3   b  and  3   c  are schematic cross sectional views of one embodiment of the latching detection and indication means according to the present invention in three different latching states. 
           [0026]      FIG. 4  is a schematic view of the electric circuit as depicted in  FIGS. 3   a - 3   c.    
           [0027]      FIG. 5  is a schematic cross sectional view of one embodiment of the latching detection and indication means of the intermediate latching state according to the present invention. 
           [0028]      FIG. 6  is a schematic view of the electric circuit as depicted in  FIG. 5 . 
           [0029]      FIG. 7  is a schematic view of the electric circuit used in one embodiment of the latching detection and indication means according to the present invention. 
           [0030]      FIGS. 8   a ,  8   b  and  8   c  are schematic cross sectional views of one embodiment of the latching detection and indication means according to the present invention in three different latching states. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    A usual method for in-flight refueling operations is illustrated in  FIG. 1  and is based on the use of a hose and drogue device  15 . This refueling method employs a flexible hose  19  that trails from a refueling unit  17  (pod or FRU) located in the tanker aircraft  13  with a drogue  21  (a fitting resembling a windsock or shuttlecock) attached at its narrow end. The receiver  11  has a probe  25 , which is a rigid arm placed on the aircraft&#39;s nose or fuselage with a valve that is closed until it mates with the end of the hose after which it opens and allows fuel to pass from the tanker aircraft  13  to the receiver aircraft  11 . 
         [0032]      FIG. 2  shows the reception coupling unit  31  at the end of the hose  19  with an external surface  33  and an internal passage  37  for receiving the probe  25 . 
         [0033]    The reception coupling unit  31  and the probe  25  shall have cooperating latching means for assuring that the probe  25  is properly connected to the hose  19  to proceed with the refueling operation. 
         [0034]    According to this invention, the reception coupling unit  31  is also provided with detection and indication means of the latching state of said cooperating latching means so that the pilot of the receiver aircraft  11  and/or the crew of the tanker aircraft  13  can receive indications concerning said latching state. 
         [0035]    Some embodiments of the invention will now be described. They may refer to a known latching system which is based on at least one roller  39  located in the internal passage  37  of the reception coupling unit  31 , that is pressed by the probe  25  by a spring-plunger assembly  41  (see  FIG. 2 ), as the cooperating means in the reception coupling unit  31 , and on a circumferential groove  29  as the cooperating means in the probe  25  (see  FIGS. 3   a ,  3   b ,  3   c ). 
         [0036]    In  FIG. 3   a , the roller  39  is at a fully extended position because it has not yet entered into contact with the probe  25 . Arrow F indicates the direction of the displacement of the incoming probe  25  with respect to the reception coupling unit  31 . 
         [0037]    In  FIG. 3   b , the roller  39  is not at a fully extended position because it is pressed by the probe  25 . 
         [0038]    In  FIG. 3   c , the roller  39  is at a fully extended position because it is inserted into the circumferential groove  29  of the probe  25 . 
         [0039]    When the roller  39  is at the fully extended position, two possible latching states can take place: the probe  25  may be fully disconnected ( FIG. 3   a ), i.e. a non-latching state, or it may be properly connected ( FIG. 3   c ), i.e. a latching state. 
         [0040]    When the roller  39  is pressed by the probe  25  ( FIG. 3   b ), an intermediate latching state takes place which means that the latching system is not locked. 
         [0041]    In one embodiment of the invention, illustrated in  FIGS. 3   a ,  3   b ,  3   c , the reception coupling unit  31  is provided with detection and indication means of the intermediate latching state of said cooperating latching means so that the pilot of the receiver aircraft  11  can receive indications concerning said latching state. 
         [0042]    The reception coupling unit  31  comprises position detectors  51 , as detection means of the latching state of the roller  39 , coupled to a switch  61  of an electric circuit  53 . 
         [0043]    The electric circuit  53  (see  FIG. 4 ) comprises an air-driven electric generator  63  and a backup battery (not shown) as electrical energy sources, a flasher component  67  and a source of light  55  placed in the external surface  33  of the reception coupling unit  31  as a first indication means of the intermediate latching state for the pilot of the receiver aircraft  11 . 
         [0044]    When the roller  39  is pressed by the probe  25  ( FIG. 3   b ), the position detector  51  closes the electric circuit  53  and the source of light  55  emits a flashing light advising the pilot of the receptor aircraft  11  of this circumstance so that he can take the required corrective actions that can lead to a proper connection. 
         [0045]    When the roller  39  is at the fully extended position ( FIGS. 3   a  and  3   c ) the electric circuit  53  remains open so that the source of light  55  is turned OFF. 
         [0046]    If the latching system has three rollers  39  spaced around the internal passage  37  of the reception coupling unit  21 , which may occur in the above-mentioned latching systems, this embodiment may comprise individual detection and indication means for each roller  39  and therefore the reception coupling unit  31  will be provided with three sources of light  55  as indication means for the pilot of the receptor aircraft  11  which will be spaced around the external surface  33  of the reception coupling unit  31  facilitating therefore that the pilot of the receptor aircraft  11  can be informed that the probe  25  is in an intermediate latching state in any position of the reception coupling unit  31 . 
         [0047]    Preferably the source of light  55  is a Light Emitting Diode (LED) device. 
         [0048]    In another embodiment of the invention, illustrated in  FIGS. 5 and 6 , the reception coupling unit  31  is provided with detection and indication means of the intermediate latching state of said cooperating latching means so that the crew of the tanker aircraft  13  can receive indications concerning said intermediate latching state. 
         [0049]    The reception coupling unit  31  comprises a position detector  51 , as detection means of the latching state of the roller  39 , coupled to a switch  61  of an electric circuit  53 . 
         [0050]    The electric circuit  53  (see  FIG. 6 ) comprises an air-driven electric generator  63  and a backup battery (not shown) as electrical energy sources, and a signal emitter  65  as a second indication means of the intermediate latching state for the crew of the tanker aircraft  13 . 
         [0051]    When the roller  39  is pressed by the probe  25  (see  FIG. 5 ), the position detector  51  closes the electric circuit  53  and the signal emitter  65  emits signals advising the crew of the tanker aircraft  13  of this circumstance so that they can take the required corrective actions that can lead to a proper connection. The tanker aircraft  13  is provided with a suitable receptor device  69  of said signals. 
         [0052]    Preferably the signal emitter  65  is a radio emitter, particularly a micro-wave radio emitter. 
         [0053]    If the latching system has three rollers  39  spaced around the internal passage  37  of the reception coupling unit  21 , which may occur in the above-mentioned latching systems, this embodiment can comprise individual detection and indication means for each roller  39  and therefore the reception coupling unit  31  will be provided with three radio emitters as indication means for the crew of the tanker aircraft  13 , or individual detection means for each roller  39  associated to a single indication means for the three rollers  39 . 
         [0054]    In another embodiment, the reception coupling unit  31  is provided with detection and indication means of the intermediate latching state of said cooperating latching means so that the pilot of the receiver aircraft  11  and the crew of the tanker aircraft  13  can receive indications concerning said latching state. 
         [0055]    As in the above-mentioned embodiments, the reception coupling unit  31  comprises a position detector  51 , as detection means of the latching state of the roller  39 , coupled to a switch  61  of an electric circuit  53 . 
         [0056]    The electric circuit  53  (see  FIG. 7 ) comprises an air-driven electric generator  63  and a backup battery as electrical energy sources, a flasher component  67 , a source of light  55  placed in the external surface  33  of the reception coupling unit  31  as a first indication means of the intermediate latching state for the pilot of the receiver aircraft  11  and a signal emitter  65  as a second indication means of the intermediate latching state for the crew of the tanker aircraft. 
         [0057]    When the position detector  51  closes the electric circuit  53 , the source of light  55  emits flashing lights and the signal emitter  65  emits signals advising, respectively, the pilot of the receptor aircraft  11  and the crew of the tanker aircraft  13  that the latching system is in an intermediate latching state so that they can take the required corrective actions that can lead to a proper connection. 
         [0058]    In another embodiment of the invention illustrated in  FIGS. 8   a ,  8   b ,  8   c , the detector  71  of the latching state of the roller  39  is an assembly of a cam  72  and a lever  73 . The lever  73  is arranged to move a pin  75 , which is the first indication means for the pilot of the receiver aircraft  11 , between a recessed and a protruding position with respect to the external surface  33  of the reception coupling unit  31 . 
         [0059]    When the roller  39  is pressed by the probe  25  ( FIG. 8   b ), the assembly of the cam  71  and the lever  73  moves the pin  75  to a protruding position making it therefore visible for the pilot of the receptor aircraft  11  so that he can take the required corrective actions that can lead to a proper connection. 
         [0060]    When the roller  39  is at the fully extended position ( FIGS. 8   a  and  8   c ) the pin  75  remains in a recessed position. 
         [0061]    The pin  75  may be understood as a body suitable to be seen by the pilot of the receiver aircraft  11  on the external surface  33  of the reception coupling unit  31  in a refueling operation. 
         [0062]    This embodiment is advisable for coupling units  31  already provided with illumination means so that they can be fully operative at night or during poor weather conditions.