Abstract:
A latch assembly for securing a nacelle portion of a gas turbine engine includes first and second nacelle flow structures that define a portion of a bypass flowpath. A seal is engageable between the first and second nacelle flow structures. A latch is rotatable about a pivot between latched and unlatched positions. The latch maintains the seal in engagement with the first and second nacelle flow structures in the latched position. A method of opening a nacelle flow structure includes the steps of pivoting a latch from a latched position to an unlatched position, and unlatching a first nacelle flow structure relative to a second nacelle flow structure in response to the latch pivoting step.

Description:
BACKGROUND 
       [0001]    This disclosure relates to a nacelle for a gas turbine engine. More particularly, the disclosure relates to a latching system configured to ensure that the latch is able to disengage and release a portion of a nacelle. 
         [0002]    One type of gas turbine engine includes a core engine that drives a fan arranged in a bypass flowpath. The bypass flowpath is provided between core and fan nacelles, the core nacelle surrounds the core engine. One example gas turbine engine includes a flow structure that provides inner and outer flow structures that define the bypass flowpath. The flow structure provides portions of the fan and core nacelles along one axial portion of the engine. 
         [0003]    The core nacelle encloses a core compartment that houses pressurized conduits, such as compressed air ducts. While the bypass flow pressure in the bypass flowpath aids in maintaining the inner flow structure in a closed and sealed position around the core flowpath, if a high pressure conduit bursts, the pressure within the core compartment may increase and separate a leading edge of the inner flow structure from its mating structure. In this condition, bypass flow may leak past the inner flow structure into the core compartment, which may destroy and dislodge portions of the core and fan nacelles. 
         [0004]    To this end, latching assemblies have been proposed, which maintain the leading edge of the inner flow structure in a fully closed position. The latching assembly may be rather complex and may be susceptible to becoming stuck, which requires surrounding structure to be disassembled and removed to gain access to the stuck latch. 
       SUMMARY 
       [0005]    In one exemplary embodiment, a latch assembly for securing a nacelle portion of a gas turbine engine includes first and second nacelle flow structures that define a portion of a bypass flowpath. A seal is engageable between the first and second nacelle flow structures. A latch is rotatable about a pivot between latched and unlatched positions. The latch maintains the seal in engagement with the first and second nacelle flow structures in the latched position. 
         [0006]    In a further embodiment of any of the above, first and second reaction load brackets are affixed relative to the first and second nacelle flow structures. One of the first and second reaction load brackets pivotally supports the latch, and the other of the first and second reaction load brackets includes a tab cooperating with the latch in the latched position. 
         [0007]    In a further embodiment of any of the above, the latch assembly includes a cable that is operatively connected to the latch and configured to rotate the latch about the pivot. 
         [0008]    In a further embodiment of any of the above, the latch assembly includes a bifurcation arranged in the bypass flowpath. The cable passes through the bifurcation. 
         [0009]    In a further embodiment of any of the above, the latch assembly includes first and second drive elements that are respectively connected to the latch and cable and are configured to transmit input from the cable to the latch. 
         [0010]    In a further embodiment of any of the above, the first and second drive elements are gears. 
         [0011]    In a further embodiment of any of the above, the latch assembly includes a handle connected to the cable. The handle is configured to actuate the latch through the cable. 
         [0012]    In a further embodiment of any of the above, the latch assembly includes a coupling that operatively connects the handle to a pair of cables. Each cable unlatches a side having the first and second nacelle flow structures. 
         [0013]    In a further embodiment of any of the above, the second nacelle flow structure is movable relative to the first nacelle flow structure about a hinge. A second nacelle flow structure provides inner and outer flow structures that define the bypass flowpath. 
         [0014]    In a further embodiment of any of the above, the inner flow structure provides a portion of the core nacelle enclosing a core compartment about a core engine. 
         [0015]    In a further embodiment of any of the above, the latch assembly includes a compressed air duct arranged in the core compartment. 
         [0016]    In a further embodiment of any of the above, the latch assembly includes a release member is operatively coupled to the latch to override a conventional latch releasing device. 
         [0017]    In a further embodiment of any of the above, the latch assembly includes a tool that is removably received by the release member during an emergency latch releasing procedure. 
         [0018]    In a further embodiment of any of the above, the latch assembly includes a thrust reverser. The thrust reverser is in an open position to receive the tool in the bypass flowpath. 
         [0019]    In another exemplary embodiment, a method of opening a nacelle flow structure includes the steps of pivoting a latch from a latched position to an unlatched position, and unlatching a first nacelle flow structure relative to a second nacelle flow structure in response to the latch pivoting step. 
         [0020]    In a further embodiment of any of the above, the method includes the step of operating a handle operatively connected to the latch. The latch pivoting step is performed in response to the handle operating step. 
         [0021]    In a further embodiment of any of the above, the method includes the step of operating a release member with a tool subsequent to a failed attempt of a conventional latch releasing procedure. 
         [0022]    In a further embodiment of any of the above, the conventional latch releasing procedure includes operating a handle operatively connected to the latch. The latch pivoting step is performed in response to the handle operating step. 
         [0023]    In a further embodiment of any of the above, the method includes the step of actuating a thrust reverser to expose a bypass flowpath, and inserting the tool into the bypass flowpath to engage the release member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0025]      FIG. 1  is a highly schematic view of an example gas turbine engine having an inner flow structure with a latch assembly. 
           [0026]      FIG. 2  is a cross-sectional area of the gas turbine engine taken along line  2 - 2  in  FIG. 1  and under normal operating conditions. 
           [0027]      FIG. 3  is a cross-sectional view similar to  FIG. 2  during a high pressure core compartment event. 
           [0028]      FIG. 4A  is a cross-sectional view illustrating the inner flow structure sealed against a mating structure during normal operating conditions. 
           [0029]      FIG. 4B  illustrates the inner flow structure unseated from its mating structure during a high pressure core compartment event shown in  FIG. 3 . 
           [0030]      FIG. 5A  illustrates the latch assembly in a latched position. 
           [0031]      FIG. 5B  illustrates the latch assembly in an unlatched position. 
           [0032]      FIG. 6  illustrates a lower bifurcation with a handle and cable for latching and unlatching the latch assembly. 
           [0033]      FIG. 7  is a cross-sectional view through the lower bifurcation along line  7 - 7  in  FIG. 6 . 
           [0034]      FIG. 8A  is a schematic view through a thrust reverser of the gas turbine engine, which provides access to a stuck latch assembly. 
           [0035]      FIG. 8B  is an enlarged view of the latch assembly illustrated in  FIG. 8A . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    An example gas turbine engine  10  is schematically illustrated in  FIG. 1 . The engine  10  includes a core engine  12  receiving a core flow C at an inlet  14 . The core flow C flows through the core engine  12  and is expelled through an exhaust outlet  16  surrounding a tail cone  20 . 
         [0037]    The core engine  12  drives a fan  18  arranged in a bypass flowpath  23 . A fan case  22  surrounds the fan  18  and provides structure for securing the engine  10  to a pylon  38  ( FIG. 2 ). The fan case  22  is housed within a fan nacelle  19 . Multiple circumferentially spaced flow exit guide vanes  24  may extend radially between the fan case  22  and the core engine  12  aft of the fan  18 . In one example, the flow exit guide vanes  24  are hollow and may accommodate wires or fluid conduits. 
         [0038]    A core nacelle  21  surrounds the core engine  12  and provides a core compartment  30 . Various components may be provided in the core compartment  30 , such as fluid conduits, for example, a compressed air duct  32 . The compressed air duct  32  is under high pressure and may supply compressed air from a low or high pressure compressor stage to a high pressure turbine stage for cooling, for example. 
         [0039]    Upper and lower bifurcations  26 ,  27  may extend radially between the fan and core nacelles  19 ,  21  in locations opposite one another to accommodate wires, fluid conduit or other components. 
         [0040]    The bypass flowpath  23  is provided by inner and outer flow structures  50 ,  51 , which provide portions of the fan and core nacelles  19 ,  21  along an axial portion of the engine  10 . A thrust reverser  28  is arranged outwardly of the outer flow structures  51  in the fan nacelle  19 . The inner flow structure  50  is secured about the core compartment  30  with a latch assembly  36 , which may be actuated by a handle  34  mounted outside the fan nacelle  19 , for example. A cable  70  ( FIGS. 6 and 7 ) may be routed from the handle  34  through one of the upper and lower bifurcations  26 ,  27  to the latch assembly  36 , for example. Additionally, latches may also be used and located as desired. The handle  34  provides a conventional latch releasing device for a conventional latch releasing procedure. 
         [0041]    Referring to  FIG. 2 , the inner and outer flow structures  50 ,  51 , which are integral with one another, are supported relative to the pylon  38  by hinges  40 . Upper and lower bumpers  42 ,  44  support the inner structure  50  relative to the upper and lower bifurcations  26 ,  27  in a desired position. During normal operation, as illustrated in  FIG. 2 , bypass pressure BP within the bypass flowpath  23  exerts a force on the inner flow structure  50  that maintains desired engagement with the upper and lower bumpers  42 ,  44 . Referring to  FIG. 3 , an undesirably high core pressure CP may result from a ruptured pressurized fluid conduit, such as the compressed air duct  32 . As a result of such a high pressure core compartment event, the inner flow structure  50  may become deformed, as illustrated on the left half of  FIG. 3 . During the event, either or both left and right side flow structures may deflect without the disclosed latch. 
         [0042]    Referring to  FIG. 4A and 4B , the inner flow structure  50  supports a seal  54  at a leading edge  52 . The seal  54  engages a flange  48  of an engine fan case structure  46  with the inner flow structure  50  being flush with the structure  46  during normal operation such that the structure  46  and inner flow structure  50  provide uninterrupted first and second nacelle flow structures. During an event in which an undesired core pressure CP is generated within the core compartment  30 , the inner flow structure  50  and seal  54  may be forced radially outward and out of engagement with the flange  48 , which permits bypass flow B in a bypass flowpath  23  to enter the core compartment  30 . Such a condition may result in damage to the core nacelle  21 . 
         [0043]    Referring to  FIGS. 5A and 5B , the latch assembly  36  is arranged near the leading edge  52  prevent deflection of the inner flow structure  50  and maintain the seal  54  in engagement with the flange  48  even if undesired core pressure CP exists. In one example, a first load reaction bracket  56  is supported by the structure  46 . A second load reaction bracket  58  is mounted to the inner flow structure  50 . The first load reaction bracket  56  includes a tab  60  that cooperates with a latch  62  pivotally mounted to the second load reaction bracket  58  to maintain the position of the inner flow structure  50  when latched, shown in  FIG. 5A . In one example, a first drive element  64  is connected to the latch  62 . A second drive element  66  cooperates with the first drive element  64  and is operably connected to the handle  34  ( FIG. 1 ) for actuation of the latch assembly  36 . In one example, the first and second drive elements  66 ,  68  are gears that transmit input to the latch  62 .  FIG. 5B  illustrates the latch  62  in an open position in which the latch  62  is disengaged from the tab  60 . Latch assembly  36  may use a different configuration of drive elements, if desired. 
         [0044]      FIGS. 6 and 7  illustrate one example routing of cables  70  interconnecting the handle  34  to the latch assembly  36 . The cable  70  rotates the latch  62  about its pivot. One cable  70  may be provided for each half of the inner flow structure  50  provided on either side of the engine  10 , illustrated in  FIG. 2 . The handle  34  may be positioned at the lower bifurcation  27 . A coupling  68  mechanically interconnects the handle  34  to cables  70 , which are arranged within a cavity  72  of the lower bifurcation  27 . 
         [0045]    Alternatively or additionally, the latch  36  may be located in the aft section of the core nacelle  21 . The latches  136 A-C may also be used to secure the left and right halves of the flow structures to one another, as best shown in  FIGS. 1 and 2 . 
         [0046]    In the event that the latch assembly  36  becomes stuck or a cable  70  breaks, a release member  80  may cooperate with the latch assembly  36  to release the latch  62  and override the conventional latch releasing procedure and provide an emergency release of the latch  62 . In one example, the thrust reverser  28  is actuated to expose the bypass flowpath  23  and the release member  80 . With the thrust reverser  28  actuated, the blocker doors  76  are disposed within the bypass flowpath  23  and the cascade assembly  74  is exposed. A tool  78  may be passed through the cascade assembly  74  into the bypass flowpath  23  to engage the release member  80 . As illustrated in  FIG. 8B , an end  84  of the tool  78  may be received in a head  82  of the release member  80 . The release member  80  may cooperate with one or more of the first and second drive elements  64 ,  66  to rotate the latch  62  out of engagement with the tab  60 . The illustration of the release member  80  is schematic. 
         [0047]    Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.