Abstract:
A latching system for releasably securing a first member to a second member in a closed position. The latching system includes a command latch assembly comprising a hook latch assembly including a handle selectively movable from a first handle position toward a second handle position and a hook member adapted to selectively engage a first keeper when the handle is in the first handle position and to disengage from the first keeper when the handle is moved to the second handle position. The latching system also includes a remotely located slave latch assembly comprising a pin latch assembly adapted to secure a second keeper to the pin latch assembly when the handle of the hook latch assembly is in the first handle position and to disengage the second keeper when the handle of the hook latch assembly is moved to the second handle position.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a latching system for releasably securing a first member to a second member in a closed position, and in particular to a latching system including a command latch adapted to operate a remotely located slave latch. 
         [0002]    Many types of latches are used in connection with aircraft to releasably secure two members or structures of the aircraft together in a closed position, such as the housing portions of an engine cowling. Such latches are subjected to substantial forces generated during use. Aircraft latches must also prevent inadvertent opening of the latch that could be caused by vibratory or other forces applied to the latch. Aircraft latches are sometimes located in substantially inaccessible locations making direct manual operation of the latch difficult if not impossible. Aircraft latches are sometimes also located in blind locations such that a latch cannot be visually inspected to confirm that the latching system is properly closed and securing the two aircraft members joined together in a closed position. 
         [0003]    Features and advantages of the disclosure will be set forth in part in the description which follows and the accompanying drawings described below, wherein an embodiment of the disclosure is described and shown, and in part will become apparent upon examination of the following detailed description taken in conjunction with the accompanying drawings. 
       SUMMARY OF THE INVENTION 
       [0004]    The disclosed device is a latching system for releasably securing a first member to a second member in a closed position. The latching system comprises a command latch assembly operatively coupled to a remotely located slave latch assembly. The command latch assembly comprises a hook latch assembly attached to the first member and a first keeper attached to the second member. The hook latch assembly includes a handle selectively manually movable from a first handle position toward a second handle position, and a hook member adapted to selectively engage the first keeper when the handle is in the first handle position and to disengage from the first keeper when the handle is moved to the second handle position. 
         [0005]    The slave latch assembly comprises a pin latch assembly adapted to be attached to the first member and a second keeper adapted to be attached to the second member. The pin latch assembly includes a pin selectively movable between a retracted position and an extended position. The pin is adapted to release the second keeper from the pin latch assembly when the pin is in the retracted position and secure the strut and the second keeper to the pin latch assembly when the pin is in the extended position. A safety device movable from a first position, wherein the safety device prevents movement of the pin to the extended position, to a second position, wherein the safety device does not prevent movement of the pin to the extended position, prevents the slave latch from closing when the slave latch in not properly positioned, thereby preventing the slave latch from closing and providing a false indication at the command latch that the second keeper has been properly secured. 
         [0006]    A coupler member has a first end operatively associated with the handle of the hook latch assembly and a second end operatively associated with the pin of the pin latch assembly such that selective movement of the handle of the hook latch assembly is adapted to move the pin of the pin latch assembly between the extended and retracted positions of the pin. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an environmental view of a latching system in accordance with an embodiment of the present disclosure. 
           [0008]      FIG. 2  is a top view of the command latch assembly. 
           [0009]      FIG. 3  is a side view of the command latch assembly, showing the handle movement as the handle is pivoted from the latched to unlatched positions. 
           [0010]      FIG. 4  is an exploded view of the hook latch assembly. 
           [0011]      FIG. 5  is a bottom perspective view of the command latch assembly in the closed position, showing the coupler attached. 
           [0012]      FIG. 6  is a perspective view of a latching system in accordance with an embodiment of the present disclosure. 
           [0013]      FIG. 7  is a perspective view of the pin latch assembly. 
           [0014]      FIG. 8  an exploded view of the pin latch assembly. 
           [0015]      FIG. 9  is a side view of the slave latch assembly with the struts fully deployed. 
           [0016]      FIG. 10   a  through  10   d  are side views of the command latch and the slave latch showing the opening sequence. 
           [0017]      FIG. 11  is a perspective view of the pin latch assembly. 
           [0018]      FIG. 12  is a view of the end of the strut and the safety device 
           [0019]      FIG. 13  is a perspective view of an alternate embodiment of the pin latch assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    While the present disclosure may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, an embodiment with the understanding that the present description is to be considered an exemplification of the principals of the disclosure and is not intended to limit the disclosure to the details of construction, methods and arrangements of components set forth in the following description or illustrated in the drawings. 
         [0021]    The present disclosure is directed to a latching system for releasably securing a first member to a second member in a closed position, such as members or panels of an aircraft, such as an engine cowling. The latching system  10  includes a command latch  12  and a remotely located slave latch  22 . 
         [0022]      FIG. 1  shows an environmental view of the latching system  10  in use latching and retaining an airplane cowling. The command latch  12  is connected to the slave latch  22  through the coupler member  30 . The command latch  12  is adapted to be coupled to the first member of an aircraft and the first keeper  16  is adapted to be coupled to a second member of an aircraft. The slave latch  22  has a pin latch  24  adapted to be coupled to the first member of an aircraft and the second keeper  26  is adapted to be coupled to a second member of an aircraft. It is to be appreciated that the presently disclosed latching system may be used in retaining other first and second members, and is not limited to the use shown in  FIG. 1 . 
         [0023]      FIGS. 2 through 5  show various views of the command latch  12 . The command latch  12  includes a hook latch assembly  14  and a first keeper  16 . The command latch  12  comprises a handle  18  having a first end  44  and a second end  78 , the handle second end  78  being pivotable about end connector  61  when the command latch  12  is activated to release both the command latch  12  and the slave latch  22 . The handle first end  44  is pivotally connected to the arms  86  and the hook member  20 , through the use of an end connector  61 , for example a pin, shaft or fastener disposed within a bushing  57 , and the handle first end  44 , arms  86 , and hook member  20  pivot about a common axis that is generally transverse to the hook member  20  longitudinal axis. The trigger  36  can have an actuator pad  90  which can be actuated by the user pressing the actuator pad  90  with their finger or an object. Pressing the trigger  36 , or the trigger  36  and the actuator pad  90 , releases the finger  92  from the trigger retention lock member  53 , and allows the handle  18  to be moved from a first handle  18  position to a second handle  18  position, wherein the handle second end  78  is raised relative to the handle first end  44 . 
         [0024]    The trigger  36  and the actuator pad  90  are manually accessible through an aperture in the top wall  19  of the handle  18  such that the trigger  36  and the actuator pad  90  may be manually pivoted from a closed position to an open position. The movement of the handle  18  from a first handle  18  position to a second handle  18  position also causes the arms  86  to be moved in the direction of the handle second end  78  and moves the arms  86  beneath the handle  18 . The movement of the arms  86  causes the coupler  30 , which is attached to the arms  86  at the coupler member first end  32 , to pull upon and activate the slave latch  22 . There can be a screwdriver slot  104  in the handle top wall  19  that provides a receptacle for the placement of a screwdriver, wherein rotation of the screwdriver causes a rotation of the screwdriver slot  104 , providing additional leverage and reducing the force necessary to open the command latch  12 . The initial movement of the handle  18  exerts no pulling motion on the arms  86  and therefore no pulling motion is transmitted to the coupler  30  through the coupler first end  32 . 
         [0025]    Shown in  FIG. 3  is a side view of the command latch  12 , and shows the movement of the command latch  12  as the trigger  36 , or the trigger  36  and actuator pad  90 , release the hook member  20  from the first keeper  16 . The trigger  36  and actuator pad  90  can act upon a finger  92  that is attached to an actuator arm  94 . The trigger retention lock member  53  has been released by the finger  92  as the handle  18  pivots upwards towards the release position. The movement of the arms  86  resulting from the pivoting of the handle  18  from a first handle  18  position to a second handle  18  position can be seen in this Figure. The handle first end  44  pivots downward as the handle second end  78  raises relative to the first keeper  16 . The hook  80  at the second end  46  of the hook member  20  can be seen gripping the first keeper  16  and then clearing and releasing the first keeper  16  as the handle  18  is raised into the unlatched position. An over-center linkage  40  includes left and right components located to either side of the hook  20 . The over-center linkage assembly  40  moves as the handle  18  is pivoted from a first handle  18  position to a second handle  18  position, releasing the trigger retention lock member  53  from the finger  92  and the first keeper  16  from the hook  80  at the second end  46  of the hook member  20 . The handle  18  has a free travel range, wherein the handle  18  moves but does not operate the slave latch  22  until the handle  18  has moved through the range of free travel, wherein the range of free travel is 10 to 20 degrees depending upon the installation. 
         [0026]      FIG. 4  is an exploded view of the hook latch assembly  14 . The handle  18  is lifted away from the hook member  20 , thereby proving clearer views of the hook member  20  and the over-center linkage assembly  40 . The hook member  20  has a first end  52  and a second end  46 , and comprises a longitudinal axis. The over-center linkage  40  comprises first links  50  and second links  54 , and the first links  50  are pivotally connected to the second links  54  through center connectors  56 , and the center connectors  56  form a mutual pivot axis for the links  50  and  54 . This axis is displaced on the links  50  and  54  from the link&#39;s  50  and  54  attachments to the rivet  38  and the bushing  57  and end connector  61 . The links  50  and  54  are arraigned in pairs on either side of the hook member  20 . The first links  50  are pivotally connected to the hook member  20  at the hook member first end  52  through an end connector  61  and a bushing  57  disposed within the hook member first end  52 . The second links  54  are pivotally connected to the rivet  38 , thereby moving the hook member  20  when the handle  18  is released from the locked position. The hook member  20  also includes upper and lower apertures  21  and  23 . The rivet  38  is moved by the over-center linkage assembly  40 . 
         [0027]    The hook  80  is located at the hook member second end  46 , and is disengaged by the movement of the over-center linkage  40  movement resulting from the activation of the trigger  36 , or the trigger  36  and the actuator pad  96 . Activation of the trigger  36 , or the trigger  36  and the actuator pad  96 , causes a finger  92  attached to an actuator arm  94  to move and release a trigger retention lock member  53  on the hook member  20 . 
         [0028]    The handle  18  includes a pair of spaced apart and generally parallel wing walls  58  and the wing walls  58  each have respective apertures  60 . The apertures  60  are operatively coupled to the center connectors  56 , and when the handle  18  is moved from the first handle  18  position to the second handle  18  position the center connectors  56  move within the apertures. The end connector  61  engages a handle aperture  202  and is disposed within the bushing  57  in the hook member first end  52 . The apertures  60  also provide for lost motion between the handle  18  and the center connectors  56  such that the over-center linkage  40  and the handle  18  may travel approximately 15 degrees before the hook  80  or the slave latch  22  begin motion. Additionally, the apertures  60  prevent the over-center linkage  40  from unlocking when the handle  18  is in the flush position. A resilient biasing member  59 , such as a spring, resiliently biases the handle  18  from the closed first position to the open second position. The screwdriver slot  104  allows a screwdriver to serve as an extension of the handle  18 , thereby providing additional leverage for the opening of the command latch  12  and the resultant operation of the slave latch  22 . 
         [0029]      FIG. 5  is a perspective view of the bottom of the command latch assembly  12 , and shows the connection of the coupler member  30  at the coupler member first end  32  to the arms  86  of the hook member  20 . The command latch  12  is adapted to be coupled to a first member of an aircraft and the keeper  16  is adapted to be coupled to a second member of an aircraft. The coupler member  30  has a coupler member first end  32  that is connected through the hook member arms  86 , end connector  61 , and bushing  57  to the first links  50  of the over-center linkage  40 , and the movement transmitted by the handle  18  through the over center linkage  40  as it is activated releases the hook member  20  from the first keeper  16 . The motion also pulls the coupler member  30  releasing the remote slave latch  22 , which is not shown. The hook member  20  has a hook member first end  52  that lies between the generally parallel wing walls  58  located at the handle first end  44 . The hook member first end  52  is attached to the apertures  202  in the wing walls  58  through an end connector  61 . The hook  80  at the second end  78  of the hook member  20  can be seen clasping the first keeper  16 , as can the finger  92  be seen grasping the trigger retention lock member  53 . The handle  18  has a free travel range of between 0.50 to 1.00 inches before the hook  80  clears the first keeper  16 . The first keeper  16  is adjacent to the handle second end  78  when the command latch  12  is the engaged or closed position. The arms  86  are connected to the coupler member first end  32 , and transmit the rotational force from the pivoting of the handle  18 . 
         [0030]    Shown in  FIG. 6  is a perspective view of the command latch  12  and the slave latch assembly  22 , along with the coupler  30 . The command latch  12  comprises a handle  18 , a hook latch assembly  14  which is connected to the first keeper  16  and an over-center linkage  40 . The hook latch assembly  14  is adapted to be attached to the aircraft first member and the first keeper  16  is adapted to be attached to the aircraft second member. A coupler member  30  is disposed between the coupler member first end  32  and the coupler member second end  34 , and transmits the movement of the coupler first end  32  to the coupler member second end  34  during operation of the latching system, wherein the coupler member  30  joins and transmits the movement from the master or command latch assembly  12  to the remote or slave latch assembly  22 . The slave latch assembly  22  comprises a pin latch assembly  24  and a second keeper  26 . The pin latch assembly  24  includes a pin  28  that is operatively connected to and operated through the operation of a cam assembly  70 . The cam assembly  70  is coupled to the coupler member second end  34  and transmits the imparted activation motion from the command latch assembly  12  to the pin latch assembly  24 . The pin latch assembly  24  has a body  68  that is adapted to be attached to the aircraft first member. There is a second keeper  26  that is adapted to be attached to the aircraft second member. If desired the slave latch assembly  22  may comprise a strut assembly which comprises a fixed strut  106  operatively connected to the body  68  of the pin latch assembly  24 , and the retractable struts  108 . 
         [0031]      FIGS. 7 through 9  show various views of the slave latch assembly  22 .  FIG. 7  is a close-up perspective view of the pin latch assembly  24 . The cam assembly  70  comprises a pair of generally parallel cam members  72 , having a first end  74  pivotally connected to the pin latch assembly body  68  through a pair of generally parallel retention members  71 , and a second end  76  operatively connected to the pin  28  through an actuator member  102 . 
         [0032]    During unlatching of the slave latch  22 , the connector second end  34  pulls the cam assembly  70  away from the pin  28  wherein the cams  72  pivot on the retention members  71  and the actuator member  102  travels along the first slot  98  to the offset second slot  100 . The actuator member  102  then reaches the full open position of the slave latch  22  wherein the pin  28  is retracted and pulled free from the second keeper  26  and the second keeper  26  is released, opening the cowling. The command latch  12  is opened further and the actuator member  102  moves further along the second slot  100 . When the command latch  12  reaches the full range of travel the actuator member  102  is at the end or terminus of the second slot  100  and the pin  28  is fully retracted from the receptacle  65  of the body  68 . The first slot  98  and the second slot  100  are offset from one another, and the actuator member  102  travels through the first slot  98  during the initial travel of the slave latch  22  unlocking operation by the command latch  12 , and completes the opening of the slave latch  22  by the command latch  12  by traveling in the second slot  100 . The slave latch  22  travels 1.27 inches from the bottom of the first slot  98  to full retraction of the pin  28  and the stop travel point of the second slot  100 . 
         [0033]    During the latching of the slave latch  22 , the actuator member  102  travels along the second slot  100  thereby extending the pin  28  into the receptacle  65  in the body  68 . Once the pin  28  is fully extended into the body  68 , the movement force shifts from pushing the pin  28  into the aperture  65  into further movement by the actuator member  102  to the end of the second slot  100  and then into the first slot  98 . The safety device  101  can comprise a spring loaded lever, which includes a biasing member  103  that biases the safety device  101  into the body  68 , whereby the safety device  101  blocks the receptacle  65  such that the pin  28  cannot enter the receptacle  65  when the pin holder  99  of the second keeper  26  has been released by the retraction of the pin  28 . The biasing member  103  biases the safety device  101  into the blocking position following retraction of the pin  28 . The second keeper pin holder  99  lifts and moves the safety device  101  away from the receptacle  65  and thus opens the receptacle  65  for entry of the pin  28  into the second keeper pin holder  99 , wherein the pin  28  retains the second keeper pin holder  99  within the body  68 . 
         [0034]    As can be seen in  FIG. 8 , the cam assembly  70  is pivotally attached to the body  68  by a pair of generally parallel retention members  71 , wherein the cam members  72  lie between the retention members  71 . The retention members  71  are attached to the body  68  through the use of connectors  69 , such as the rivets that are shown. The pin  28  enters into and operates within a pair of apertures  65  that retain and align the pin  28  during the operation of the slave latch  22 . The pin  28  can have a beveled end that would mate with a matching bevel on the inside surface of the aperture  65  opposite the cam assembly  70 . The body  68  can be attached to the fixed strut  106  through a pair of generally opposed leaf springs  67 , and connectors  69  such as the rivets that are shown. The slave latch  22  is reengaged by the reversal of the coupler  30  movement wherein the cam assembly  70  pivots and the actuator member  102  travels through the second slot  100  and then through the offset first slot  98 . The second keeper pin holder  99  will have moved the safety device  101  out of the pin&#39;s  28  path such that the pin  28  enters into receptacle  65  and retains the second keeper pin holder  99 . 
         [0035]    Shown in  FIG. 9  is a side view of the slave latch assembly  22  with the fixed strut  106  and the retractable struts  108  fully deployed. The pin latch assembly  24  is moved away from the second keeper  26 , and the first aircraft member and the second aircraft members are released from engagement with one another. The slave latch  22  can serve as a second member support such that a hinge is not required, although a hinge may be used if desired. The first aircraft member and the second aircraft members are brought into engagement following the retraction of the retractable struts  108  fully into the fixed strut  106 , and the reengagement of the pin  28  into the second keeper pin holder  99 . The retractable struts  108  retract into the fixed strut  106 , and a resilient compression means  109 , such as the spring shown, is compressed by the movement of the retractable struts  108 . The compression means  109  assists in deploying the retractable struts  108  from the fixed strut  106 , when the pin  28  is retracted and releases the second keeper  26 . The strut assembly has an extendable length of approximately 20 inches to 60 inches. 
         [0036]      FIGS. 10   a  through  10   d  show the command latch  12  and the slave latch  22  in the stages of opening from the fully closed position of  10   a  to the filly open position of  10   d.  In  FIG. 10   a  the handle  18  is adjacent to the hook member  20  and the hook  80  is clasping the first keeper  16 . The first  32  and second  34  ends of the coupler  30  have not moved, and therefore the cam  72  is also in an umnoved position. In  FIG. 10   b  the handle  18  has moved to the end of the free travel, and the handle  18  is no longer adjacent to the hook member  20  but the slave latch  22  has not begun to open. The hook  80  is still clasping the first keeper  16  and the slave latch  22 , and therefore the cams  72 , have not been moved as the coupler first end  32  has not transmitted any motion to the coupler  30  and then onward to the coupler second end  34 . 
         [0037]    As can be seen in  FIG. 10   c,  the handle  18  is partially through the range of movement to open the slave latch  22 . The hook  80  of the hook member  20  has released the first keeper  16  and the finger  92  is likewise clear of the trigger retention lock member  53 . The first link  50  of the over center linkage  40  has begun to pivot away from the second link  54 . The coupler first end  32  has moved and the coupler  30  has transmitted this movement to the coupler second end  34 . The cams  72  have pivoted, and the actuator member  102  has moved out of the first slot  98  and into the second slot  100 . The pin  28  has started its movement away from the body  68 , and the second keeper  26  will have entered the initial release stages. In  FIG. 10   d  the command latch  12  has completed the full range of travel, and is now completely open. The slave latch  22  has also completed its full range of travel, and the pin  28  has retracted and released the second keeper  26 . The actuator member  102  is at the end of the second slot  100 . The finger  92  and trigger retention lock member  53  are separated, as are the hook  80  and first keeper  16 . The first link  50  of the over center linkage  40  can be seen pivoted away from the second link  54 . 
         [0038]    Shown in  FIG. 11  is a view of the pin latch assembly  24 , and the cam assembly  70  is at the mid-way point of closing the command latch  12 . The pin  28  is fully extended into the receptacle  65  and the safety device  101  is lifted out of position by the second keeper pin holder  99 . The pin  28  is in the second keeper pin holder  99 . The actuator member  102  is in the second slot  100  of the cams  72 , and the cams  72  have pivoted on the retention members  71  that are attached to the body  68 . An alternate connection for the connector second end  34  is shown. 
         [0039]      FIG. 12  shows the second keeper pin holder  99  that is retained by the pin  28  removed from the body  68  of the pin latch assembly  24 . The safety device  101  is biased into the receptacle  65  of the body  68  and would thus block entry by the pin  28  into the receptacle  65 , thereby preventing the slave latch  22  from closing when the slave latch  22  in not properly positioned, and thereby preventing the slave latch  22  from closing and providing a false indication at the command latch  12  that the second keeper  26  has been properly secured. 
         [0040]      FIG. 13  shows an alternate embodiment of the pin latch assembly  24 . Two connectors  30  are shown and each has a connector second end  34 . The actuator member  102  moves within a first slot  98  and a second slot  100  while moving the pin  28 . The pin  28  travels within the receptacle  65  and biases the safety device  101  away from the receptacle  65 . The cam assembly  70  comprises cams  72  that are pivotally attached to the body  68 . 
         [0041]    The command latch and the slave latch operate cooperatively to latch and lock two adjacent members or panels of an aircraft. The slave latch can be, though need not be, located in an inaccessible location once the airplane is constructed. The command latch and slave latch are joined by a cable or similar flexible bond that is capable of transmitting the force and or movement motion generated by the operation of the command latch to the slave latch. The slave latch has a fixed strut and deployable struts that move away from the pin latch when the latch is released, thereby allowing the joined first and second members to be opened for repairs or inspection of the components contained within the covers. The slave latch supports the weight of the engine cowling such that a hinge is not needed, although one or more may be provided. There is a free range of travel by the command latch, wherein the command latch moves in the range of 10 to 20 degrees from the initial closed and flush position where the handle is flush with the outer skin of the airplane, to an initial opening stage where the command latch has been lifted away from the skin but has not begun to unlatch or operate upon the slave latch. 
         [0042]    The activation of the trigger, or the trigger and the activation pad, followed by a lifting of the handle moves the finger away from the trigger retention lock member. The movement of the handle during the free travel movement does not move the linkages of the over center linkages. As the handle is moving during the free range of travel the slave latch does not receive movement from the coupler and therefore the slave latch does not begin movement. After the handle has completed the free travel movement the over center linkage starts movement as does the coupler, thereby initiating movement of the slave latch. The over center linkage connector member begins movement along the longitudinal slot of the hook member, and the finger of the hook member begins to release the first keeper. The slave latch attains a fully open position, wherein the pin has been withdrawn from and releases the retractable strut when the command latch has completed about  70  to  80  percent of its travel range. At this position the actuator member is not at the end of the second slot of the cam member. The continued motion of the command latch after it attains the full opening travel range continues to pull on the coupler and moves the actuator member to the end of the second slot in the cam member and therefore pulls the pin further out of the body receptacle but does not result in further movement of the strut assembly. 
         [0043]    While the above is a description of various embodiments of the present invention, further modifications may be employed without departing from the spirit and scope of the present invention. Thus the scope of the invention should not be limited by the specific structures disclosed. Instead the true scope of the invention should be determined by the appended claims.