Abstract:
An apparatus and method according to one or more embodiments are provided for a latching mechanism. The latching mechanism may be implemented, for example, as a positive lock latching mechanism that provides a positive indication when a latch is not engaged. In one example, an apparatus includes a latch arm comprising a slotted hole and a latch hook configured to engage a pin. The latch includes a bifold handle coupled to the latch arm, the bifold handle comprising a first handle portion and a handle extension portion, wherein the first handle portion comprises a lock hook configured to translate through the slotted hole to engage the pin and the handle extension portion is configured to move away from the first handle portion when the lock hook is not engaged with the pin. Additional systems and methods are also provided.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates generally to latching mechanisms for hinged structures and, more particularly, for example, to latching mechanisms used on modern airline engine fan cowls. 
       BACKGROUND 
       [0002]    In the field of latching mechanisms such as for modern aircraft, there is an ongoing effort to assure that structures required to be latched are properly latched prior to flight. During normal operation, hinged structures are unlatched and opened to provide access by operators and ground support personnel. The structures need to be closed and securely latched prior to flight operation. Conventional latching mechanisms provide a latch and latch handle to engage and latch hinged structures. Further, conventional latches lock the latch handle to the latch such that the latch handle can be folded flush with an exterior surface of the hinged structure. If a latch is not properly latched, the latch handle may protrude from the exterior surface of the hinged structure to provide an indication to an operator the latch is not secured. However, the handle may not be visible to an operator due to line of sight restrictions relative to the latch. Further, a latch handle may be secured while the latch itself is not properly engaged with the mating structure. 
         [0003]    Thus, there is a need for a latch mechanism that provides a high degree of visibility when the latch mechanism is not fastened so that an unfastened or un-latched condition can be easily detected. Further, there is a need to provide a positive indication that the latch is properly engaged. 
       SUMMARY 
       [0004]    Systems and methods are disclosed herein in accordance with one or more embodiments that provide an improved approach to latching modern airliner engine fan cowls and providing a positive indication the latch mechanism is closed. In some embodiments, a latch is implemented with a latch arm pivotally secured to a first cowl configured to engage a pin on a second cowl. In one example, a slotted hole is formed in the latch arm to allow a lock hook to freely translate through the slotted hole to engage the pin. The lock hook is coupled to a bifold handle and configured such that the bifold handle will not close until the lock hook is engaged on the pin. A handle extension moves away such that it is easily visible by an observer when the latch hook is not engaged with the pin. 
         [0005]    In one embodiment, a latch includes a latch arm comprising a slotted hole and a latch hook configured to engage a pin; and a bifold handle coupled to the latch arm, the bifold handle comprising a first handle portion and a handle extension portion, wherein the first handle portion comprises a lock hook configured to translate through the slotted hole to engage the pin and the handle extension portion is configured to move away from the first handle portion when the lock hook is not engaged with the pin. 
         [0006]    In another embodiment, a method of using a latch includes moving a latch arm from a first position to a second position; securing the latch arm at the second position; moving a first handle member from a third position to the second position; securing the first handle member at the second position, wherein securing the first handle member comprises moving a catch pin from a resting position to a center position; and moving a handle extension member into a secured position adjacent to the first handle member. 
         [0007]    The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates a line of sight view of a latch on an engine fan cowl in accordance with an embodiment of the disclosure. 
           [0009]      FIG. 2  illustrates engine fan cowls mounted to an engine in accordance with an embodiment of the disclosure. 
           [0010]      FIGS. 3A and 3B  illustrate perspective views of latches secured to an engine fan cowl in accordance with embodiments of the disclosure. 
           [0011]      FIG. 4  illustrates an engaged latch in accordance with an embodiment of the disclosure. 
           [0012]      FIGS. 5 and 6  illustrate inside views of a latch in accordance with embodiments of the disclosure. 
           [0013]      FIG. 7A  illustrates a view of an adjustment mechanism of a latch in accordance with an embodiment of the disclosure. 
           [0014]      FIG. 7B  illustrates a cutaway view of an adjustment mechanism of a latch in accordance with an embodiment of the invention. 
           [0015]      FIGS. 8A and 8B  illustrate a catch pin mechanism of a latch in accordance with embodiments of the disclosure. 
           [0016]      FIG. 9  illustrates a lock hook mechanism of a latch in accordance with an embodiment of the disclosure. 
           [0017]      FIGS. 10A-E  illustrate operational perspectives of a latch in accordance with embodiments of the disclosure. 
       
    
    
       [0018]    Embodiments of the invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. 
       DETAILED DESCRIPTION 
       [0019]    Conventional latching mechanisms provide a latch and a latch handle to engage and latch engine fan cowls. Conventional latches may lock the latch handle to the latch such that the latch handle can be closed and locked without actually fastening the two engine fan cowls together. 
         [0020]    Further, existing engine fan cowl latches provide limited visual indication of the latch condition. A conventional closed latch that is not fastened may protrude only 1 or 2 inches. Latches on the bottom of the engine fan cowl of airplanes with low slung engines do not protrude enough to be visible by an observer near the engine due to the curvature of the engine fan cowl. 
         [0021]    As set forth above, these approaches fail to provide an indication a latch is not properly secured resulting in an open engine fan cowl. A latching mechanism is described herein that provides a positive indication that a latch is properly secured and a visible indication when the latch is not properly secured. 
         [0022]      FIG. 1  illustrates a line of sight view of a latch on an engine fan cowl  100  in accordance with an embodiment of the disclosure. In  FIG. 1 , a latch  101  is shown in an unlatched condition. Latch  101  is used to secure a pair of hinged cowls covering an engine  105 . Engine  105  is secured to a wing  103 .  FIG. 1  illustrates that an observer  107  is unable to view latch  101  in an unlatched condition at a line of sight  109  (e.g., line of sight of conventional latch handles) due to the curvature of engine  105 . Thus, low slung engines such as engine  105  require a longer handle than that provided by conventional latches in order to be detected by observer  107  when the latch is not properly latched. Positive lock latching mechanism, latch  102  (not shown) includes a longer handle such that an unlatched condition may easily be detected. 
         [0023]      FIG. 2  illustrates engine fan cowls mounted to an engine  200  in accordance with an embodiment of the disclosure. In  FIG. 2 , engine  105  is shown with two adjacent hinged engine fan cowls  211  and  213  secured to engine  105 . Engine fan cowl  211  and engine fan cowl  213  are shown in an open position. A plurality of latches  102  may be secured to engine fan cowl  211  near a mating surface  201 . Latches  102  may be used to latch engine fan cowl  211  and engine fan cowl  213  together at mating surface  201  and mating surface  218  when they are moved to a closed position at a bottom surface of engine  105 . 
         [0024]      FIG. 3A  illustrates an inside view of an engine fan cowl  300  in accordance with an embodiment of the disclosure. In  FIG. 3A , an inside view of engine fan cowl  211  is shown with three latches (e.g.,  102   a ,  102   b  and  102   c ). Latches  102   a ,  102   b  and  102   c  are shown secured to engine fan cowl  211  by fastener bolts  320 . Latches  102  may be secured to engine fan cowl  211  near mating surface  201 . Cowl guide pins  215  may be located near each latch  102  to aid in positioning the mating surfaces of engine fan cowl  211  and engine fan cowl  213  when latching. 
         [0025]      FIG. 3B  illustrates an outside view of an engine fan cowl  301  in accordance with an embodiment of the disclosure.  FIG. 3B  illustrates engine fan cowl  211  including latches  102   a ,  102   b  and  102   c  secured to engine fan cowl  211 . Latch  102  includes a latch arm  304  and a bifold handle  315 . 
         [0026]    Latch arm  304  includes a latch hook  306  and a slotted hole  308  formed within latch arm  304 . Latch hook  306  is located on an end of latch arm  304  and is formed on a top surface of latch arm  304  to engage a pin  424  (see  FIG. 4 ). Slotted hole  308  may be formed within latch arm  304  from a first side of latch hook  306  through to a second side of latch hook  306 . Slotted hole  308  is elongated to allow a lock hook  310  to pass through slotted hole  308 . 
         [0027]    Bifold handle  315  includes a first handle portion  312  and a handle extension portion  314 . First handle portion  312  includes lock hook  310 . In some embodiments, lock hook  310  may be secured on a first end of first handle portion  312  such that when first handle portion  312  is moved toward latch arm  304 , lock hook  310  translates through slotted hole  308  to engage pin  424 . In other embodiments, lock hook  310  may translate adjacent to latch arm  304  to engage pin  424 . 
         [0028]    Handle extension portion  314  may be pivotally coupled to first handle portion  312  at handle extension coupling  316 . Handle extension portion  314  includes one open side to fold adjacent to first handle portion  312 . Handle extension portion  314  may move (e.g., rotate) toward first handle portion  312  to a secure position when latch  102  is engaged. Handle extension portion  314  may move away from first handle portion  312  when latch  102  is not engaged. Bifold handle  315  is shown moved away from latch arm (when latch  102  is not engaged) in  FIG. 3B . In some embodiments, handle extension portion  314  rotates to a secured position. However, other embodiments are possible where handle extension portion  314  may slide into a secure position when latch  102  is engaged. 
         [0029]      FIG. 4  illustrates an engaged latch  400  in accordance with an embodiment of the disclosure. In  FIG. 4 , latch  102  is engaged with pin  424 . Latch  102  may be pivotally secured to a first cowl member by cowl fastener bolt  320  (see  FIG. 3 ). Pin  424  may be physically secured to a second cowl member. Latch hook  306  is shown engaged with pin  424 . Lock hook  310  is positioned through slotted hole  308  and engaged with pin  424 . In this regard, lock hook  310  translates through slotted hole  308  to engage pin  424 . 
         [0030]    Handle extension portion  314  is shown in a secured position. In this regard, handle extension portion  314  may fold in (e.g., rotates or moves) at handle extension coupling  316  adjacent to first handle portion  312  when lock hook  310  is engaged with pin  424 . 
         [0031]    Additional elements included are an adjustment nut lock fastener  423  used to secure adjustment nut  562  after selectively adjusting a latch  102  preload, as described herein. Further, a latch body  421  pivotally secures a double hinged lever  528  (see  FIG. 5 ) at a latch body mount  425 . 
         [0032]      FIGS. 5 and 6  illustrate inside views of a latch in accordance with embodiments of the disclosure.  FIG. 5  provides an inside view of latch  102 .  FIG. 6  also provides an inside view of latch  102  with additional elements discussed herein. These views aid in illustrating an embodiment of the disclosure and the detailed discussion herein may refer to these views and elements contained within these views. 
         [0033]      FIG. 5  illustrates latch  102  with partially folded bifold handle  315  and latch arm  304 . Bifold handle  315  includes a first end of first handle portion  312  coupled to latch arm  304  at first handle attach through hole  532 . When first handle portion  312  rotates at a first handle attach through hole  532  from a latch  102  open position, it may exert a force on a double hinged lever  528  at a latch arm mount  530  to move latch arm  304  toward pin  424 . A latch arm guide  556  guides latch arm  304  at a latch arm guide hole  554 , formed as part of latch arm  304 . As first handle portion  312  further rotates, latch hook  306  may be pulled over pin  424  to move a first cowl toward a second cowl. Latch  102  may be pivotally secured to a cowl at latch through hole  526 . A latch body  421  pivotally secures a double hinged lever  528  at a latch body mount  425 . 
         [0034]    Lock hook  310  may be coupled to first handle portion  312  at lock hook pivotal connection  552 . As first handle portion  312  moves toward pin  424 , lock hook  310  translates through slotted hole  308  and may be pushed over pin  424  to engage pin  424 . Lock hook  310  may be coupled to lock hook spring and linkage  546  at lock hook attach pin  550 . Linkage portion of lock hook spring and linkage  546  may limit travel of lock hook  310  by a stop located near lock hook spring connection  550 . 
         [0035]    As lock hook  310  moves, lock hook spring and linkage  546  translate longitudinally relative to lock hook  310 . Spring portion of lock hook spring and linkage  546  may hold lock hook  310  in a resting (e.g., closed or forward) position when lock hook  310  is not engaged with pin  424 . Linkage portion of lock hook spring and linkage  546  may be coupled to a latch release button  544  at coupling  549 . Latch release button  544  may be secured to first handle portion  312  at a pivotal coupling  542 . Latch release button  544  may be coupled to a catch pin  536  at a catch pin linkage  548 . 
         [0036]    Catch pin  536  may be a rod traversing first handle portion  312  and may translate longitudinally along a long side of first handle portion  312  through elongated slotted holes  540 . Slotted hole  540  may be formed on two sides of first handle portion  312 . Other embodiments may include only one slotted hole or multiple slotted holes. Catch pin  536  moves along slotted hole  540  relative to lock hook  310 . 
         [0037]    The movement of lock hook  310  and catch pin  536  position lock hook  310  relative to first handle portion  312 . When lock hook  310  engages pin  424 , pin  424  may move lock hook  310 . Lock hook  310  may have an angled lead designed to contact pin  424  and facilitate engaging pin  424  by providing a force to move lock hook  310  to a position where pin  424  may contact the inner radius of lock hook  310 . In some embodiments, lock hook  310  may move catch pin  536  to one of a plurality of positions within slotted hole  540 . In certain such embodiments, lock hook  310  may move catch pin  536  to one of three positions. The three positions of catch pin  536  are resting, center and release. Lock hook  310  may move catch pin  536  to the resting and center positions. Engagement of a latch release button  544  may move catch pin  536  to the release position. When latch release button  544  is depressed, lock hook  310  disengages with pin  424  and catch pin  536  moves to the release position. 
         [0038]    Bifold handle  315  may include a second end of first handle portion  312  coupled to handle extension portion  314  at handle extension coupling  316 . Handle extension portion  314  provides for visual indication that lock hook  310  is not engaged with pin  424 . In this regard, handle extension portion  314  includes a handle catch  538  fixedly attached to both sides of handle extension portion  314 . Handle catch  538  may contact catch pin  536  in a locked position to prevent handle extension portion  314  from moving away from first handle portion  312 . In this regard, catch pin  536  translates to contact handle catch  538  in the locked position when lock hook  310  is engaged with pin  424  to keep handle extension portion  314  adjacent to first handle portion  312 . Further, catch pin  536  may translate away from handle catch  538  or be in the resting position when lock hook  310  is not engaged with pin  424  to allow handle extension portion  314  to move away from first handle portion  312 . Handle extension portion  314  is forced away from first handle portion  312  by handle extension tensioner  534 . 
         [0039]    Latch  102  includes a latch adjustment mechanism  566 . Latch adjustment mechanism  566  includes a latch spindle  560 , a latch spindle threaded shaft  558 , an adjustment nut  562  including threaded holes  567  spaced around the perimeter of adjustment nut  562 , a tab lock washer  564  and an adjustment nut lock fastener  423 . As further discussed herein, latch adjustment mechanism  566  is used to selectively adjust a preload of latch  102 . 
         [0040]    In  FIG. 6 , latch  102  includes a first handle spring mechanism  669  to apply a force to first handle portion  312  to move first handle portion  312  relative to latch arm  304  when lock hook  310  is not engaged with pin  424 . In this regard, first handle spring mechanism  669  may be a coil spring positioned on a first end at a ledge protrusion on double hinged lever  528  and positioned on a second end at the inside base of first handle portion  312 . Other embodiments may substitute other force applying devices, such as leaf springs, bushings, torsion bars, tension springs, etc. in place of coil springs. Handle spring mechanism  669  maintains first handle portion  312  in tension to force first handle portion  312  to move away from latch arm  304  unless lock hook  310  is engaged with pin  424 . Latch hook  306  also engages pin  424 . 
         [0041]    Lock hook  310  may be coupled to first handle portion  312  at lock hook pivotal connection  552 . Lock hook  310  may be coupled to lock hook spring and linkage  546  at lock hook attach pin  550 . Lock hook  310  may move catch pin  536  to one of a plurality of positions within slotted hole  540  as discussed herein. 
         [0042]    Latch  102  includes a handle extension spring mechanism  668  to apply a force to handle extension portion  314  to move handle extension portion  314  relative to first handle portion  312  when lock hook  310  is not engaged with pin  424 . Handle extension spring mechanism  668  may be a coil spring positioned on a first end at a bottom surface of latch arm  304  near latch arm mount  530  and positioned on a second end at handle extension tensioner  534 . Handle extension spring mechanism  668  maintains a force on handle extension tensioner  534 . Handle extension tensioner  534  may be pivotally secured to first handle portion  312  at a top surface and extends through a slotted hole in first handle portion  312  to contact a top surface of handle extension portion  314 . Handle extension portion  314  is forced away from first handle portion  312  by handle extension tensioner  534 . In this regard handle extension portion  314  pivotally rotates away from first handle portion  312  at handle extension coupling  316 . In certain embodiments, two or more handle extension spring mechanisms  668  and two or more handle extension tensioners  534  may be used, each located at the top surface of first handle portion  312 . In other embodiments, handle extension spring mechanism  668  may be used to force handle extension portion  314  away from first handle portion  312 . 
         [0043]    Latch release button  544  includes a latch release spring  670 . In some embodiments, latch release spring  670  may be a coil spring positioned on a first end at latch release button  544  and positioned on a second end at first handle portion  312 . In other embodiments, latch release spring  670  may be a tension or a compression spring. 
         [0044]    Latch  102  includes a latch adjustment mechanism  566  contained within latch body  421 . Latch adjustment mechanism  566  includes a latch spindle  560 , a latch spindle threaded shaft  558 , an adjustment nut  562  including threaded holes  567  spaced around the perimeter of adjustment nut  562 , a tab lock washer  564  and an adjustment nut lock fastener  423 . As further discussed herein, latch adjustment mechanism  566  may be used to selectively adjust a preload of latch  102  by changing the distance between fastener bolt  320  and pin  424 . Latch  102  may be pivotally secured to a cowl at latch through hole  526 . 
         [0045]    Also included are latch arm guide  556  and latch arm guide through hole  554 . Latch arm guide  556  guides latch arm  304  through latch arm guide hole  554  as latch arm  304  moves (e.g., to engage pin  424 ). Further, a latch body  421  pivotally secures a double hinged lever  528  at a latch body mount  425 . 
         [0046]      FIG. 7A  illustrates a view of an adjustment mechanism of a latch  700  in accordance with an embodiment of the disclosure.  FIG. 7B  illustrates a cutaway view of an adjustment mechanism of a latch  701  in accordance with an embodiment of the invention. These views aid in illustrating an embodiment of the disclosure and the detailed discussion herein may refer to these views and elements contained within these views. 
         [0047]    Latch adjustment mechanism  566  applies a selectable preload to latch  102  by adjusting the position of latch body  421  relative to latch through hole  526 . Latch adjustment mechanism  566  is formed as an integral part of latch body  421 . Latch body  421  with latch adjustment mechanism  566  is pivotally secured to a cowl at latch through hole  526 , latch through hole  526  may be formed within latch spindle  560 . In this regard, as adjustment nut  562  is turned on latch spindle threaded shaft  558 , latch body  421  moves relative to latch through hole  526 . Additionally, such a configuration allows the effective length of latch arm  304  (i.e., the distance between the latch hook  306  and the fastener bolt  320 , both not shown) to be adjusted without adjusting the effective length of the first handle portion  312  (i.e., the distance between lock hook  310  and fastener bolt  320 ). Adjustment may be performed when latch arm  304  is engaged with pin  424 . Thus, as adjustment nut is turned, latch  102  moves to preload or change the preload of latch arm  304  on pin  424 . In some embodiments, adjustment nut  562  may include one or more holes  567  spaced around the perimeter of adjustment nut  562 . In other embodiments, spline teeth may be oriented around an outside diameter of adjustment nut  526 . An adjustment nut lock fastener  423  and a tab lock washer  564  may be used to secure adjustment nut  562  to set and/or keep a preload. In certain embodiments, lock wire or a friction locking device may be used to secure adjustment nut  526 . In other embodiments, adjustment nut  562  may include detents to receive a ball lock or other mechanical retention features. 
         [0048]    In certain embodiments where a preload is not required, latch body  421  may be pivotally connected to fastener bolt  320 . 
         [0049]    Also included are latch arm guide  556  and latch arm guide through hole  554 . Latch arm guide  556  guides latch arm  304  through latch arm guide hole  554  as latch arm  304  moves (e.g., to engage pin  424 ). 
         [0050]      FIGS. 8A and 8B  illustrate a catch pin mechanism of a latch  800  and  801 , respectively, in accordance with embodiments of the disclosure. 
         [0051]      FIG. 8A  illustrates portions of latch  102  that interface with handle extension portion  314 . Linkage portion of lock hook spring and linkage  546  is coupled to a first end of latch release button  544  at coupling  549 . Latch release button  544  is coupled at a second end to a catch pin linkage  548  portion of catch pin  536 . Latch release button  544  is pivotally secured to first handle portion  312  at a pivotal coupling  542 . Catch pin  536  translates through slotted hole  540 . 
         [0052]    Double hinged lever  528  may be pivotally secured to first handle portion  312  and latch arm  304  ( FIG. 3 ). Rotation of first handle portion  312  may exert a force on double hinged lever  528  to move latch arm  304  ( FIG. 3 ) toward pin  424  ( FIG. 4 ). 
         [0053]    In  FIG. 8A , catch pin  536  is shown in a position when lock hook  310  ( FIG. 3 ) is engaged with pin  424 . In this regard, catch pin  536  is in a center position and handle catch  538  is in a locked position in contact with catch pin  536  and handle extension portion  314  is secured adjacent to first handle portion  312 . 
         [0054]    Catch pin  536  translates relative to lock hook  310 . In this regard, as lock hook  310  is disengaged from pin  424 , catch pin  536  translates away from handle catch  538  allowing handle extension portion  314  to move away from first handle portion  312 . 
         [0055]    Movement of catch pin  536  along slotted hole  540  provides a positive indication that latch arm  304  is secured or not secured. In this regard, lock hook  310  will not engage with pin  424  if latch hook  306  ( FIG. 3 ) is not engaged with pin  424 . Position of lock hook  310  is translated relative to catch pin  536  through coupling  549  of lock hook spring and linkage  546 . Thus, if lock hook  310  is not engaged with pin  424 , catch pin  536  will not move to a center position. When catch pin  536  is not in the center position, catch pin  536  may not support handle catch  538  and, accordingly, handle extension portion  314 . Thus, handle extension portion  314  moves away from first handle portion  312  to provide a positive visual indication to an observer latch  102  is not properly engaged. This positive latch mechanism provides a failsafe approach to insuring a latch is properly engaged. 
         [0056]    Further, latch release button  544  disengages lock hook  310  from pin  424  when latch release button  544  is depressed. Catch pin  536  translates away from handle catch  538  when latch release button  544  is depressed to allow handle extension portion  314  to move away from first handle portion  312 . 
         [0057]      FIG. 8B  illustrates three positions of catch pin  536 . Catch pin  536  is in the center position ( 802 ) when lock hook  310  is engaged with pin  424 . In this configuration, handle catch  538  is in contact with catch pin  536  and handle extension portion  314  may be secured adjacent to first handle portion  312 . 
         [0058]    Catch pin  536  translates to a resting position ( 806 ) when lock hook  310  is not engaged with pin  424 . In this configuration, catch pin  536  translates away from handle catch  538  allowing handle extension portion  314  to move away from first handle portion  312 . 
         [0059]    Catch pin  536  translates to a release position ( 804 ) when latch release button  544  is depressed. In this configuration, lock hook  310  disengages from pin  424  and catch pin  536  translates away from handle catch  538  allowing handle extension portion  314  to move away from first handle portion  312 . 
         [0060]      FIG. 9  illustrates a lock hook mechanism of a latch  900  in accordance with an embodiment of the disclosure. In  FIG. 9 , cutaway  901  shows lock hook  310  connected to first handle portion  312  at lock hook pivotal connection  552 . Lock hook spring and linkage  546 , connected to lock hook  310  at lock hook attach pin  550 , may limit the travel of lock hook  310  relative to latch hook  306  to keep lock hook  310  from contacting latch hook  306 . Spring member of lock hook spring and linkage  546  may hold lock hook  310  in a closed (e.g., resting) position when lock hook  310  is not engaged with pin  424 . The implementation of lock hook spring and linkage  546  coupling to lock hook  310  allows latch  102  to be adjusted (e.g., preloaded) without requiring additional adjustments to lock hook  310  travel relative to latch hook  306 . A cavity  902  is included in first handle portion  312  to guide lock hook  310  travel. Handle extension coupling  316  couples handle extension portion  314  to first handle portion  312 . 
         [0061]      FIGS. 10A-E  illustrate operational perspectives of a latch  1000  in accordance with embodiments of the disclosure.  FIG. 10  includes  FIGS. 10A, 10B, 10C, 10D and 10E  to illustrate latch  102  in operation. 
         [0062]      FIGS. 10A, 10B, 10C, 10D and 10E  include a first cowl member  1005  with a latch  102  mechanically coupled on first cowl member  1005  and a second cowl member  1006  with a pin  424  mechanically coupled on second cowl member  1006 . 
         [0063]      FIG. 10A  ( 1000 ) illustrates latch  102  in an unengaged position. First handle member  312  is in an unsecured (e.g., third) position. Handle extension member  314  is unsecured. Both latch hook  306  and lock hook  310  do not engage pin  424 . Latch arm  304  is in a first (e.g., unsecured) position. Handle extension member  314  is moved away from first handle member  312 . 
         [0064]      FIG. 10B  ( 1001 ) illustrates latch  102  in a disengaged position. First handle member  312  is in an unsecured (e.g., third) position. Handle extension member  314  is unsecured. Latch hook  306  is engaged. Lock hook  310  is not engaged. Latch arm  304  is in a second (e.g., secured) position. Handle extension member  314  is moved away from first handle member  312 . 
         [0065]      FIG. 10C  ( 1002 ) illustrates latch  102  in a further disengaged position. First handle member  312  is in an unsecured (e.g., third) position. Handle extension member  314  is unsecured. Latch hook  306  is engaged. Lock hook  310  is not engaged. Latch arm  304  is in a second (e.g., secured) position. Handle extension member  314  is moved away from first handle member  312 . 
         [0066]      FIG. 10D  ( 1003 ) illustrates latch  102  in another disengaged position. First handle member  312  is in an unsecured (e.g., third) position. Handle extension member  314  is unsecured. Latch hook  306  is engaged. Lock hook  310  is not engaged. Latch arm  304  is in a second (e.g., secured) position. Handle extension member  314  is moved away from first handle member  312 . 
         [0067]      FIG. 10E  ( 1004 ) illustrates latch  102  in an engaged position. First handle member  312  is in a secured (e.g., second) position. Handle extension member  314  is in a secured (e.g., second) position. Latch hook  306  is engaged. Lock hook  310  is engaged. Latch arm  304  is in a second (e.g., secured) position. Handle extension member  314  is folded in adjacent to first handle member  312 . 
         [0068]    Embodiments described above illustrate but do not limit the invention. For example, it will be appreciated that, where appropriate, principles applied herein to latches used on aircraft hinged structures can be applied to latching other hinged structures. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.