Abstract:
A latch mechanism for releaseably latching or holding a first member with respect to a second member in a structure. The latch mechanism includes a bolt assembly, mounting brackets, and a locking trigger. The latch mechanism also includes a rotatable locking cam for providing retention of the bolt assembly in a latched or locked condition.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 61/025,294, filed Jan. 31, 2008. The disclosure set forth in the referenced provisional application is incorporated herein by reference in its entirety, including all information as originally submitted to the United States Patent and Trademark Office. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a latch mechanism for releaseably latching or holding a first member with respect to a second member in a structure. The latch mechanism includes a bolt assembly, mounting brackets, and a locking trigger. The latch mechanism also includes a rotatable locking cam for providing retention of the bolt assembly in a latched or locked condition. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    The present disclosure will be described hereafter with reference to the attached drawings which are given as a non-limiting example only, in which: 
           [0004]      FIG. 1  is a perspective view of the latch assembly installed in a structure, as viewed from above the structure; 
           [0005]      FIG. 2  is a side elevational view showing the latch in a closed and in an open position; 
           [0006]      FIG. 3  is a top plan view; 
           [0007]      FIG. 4  is an exploded perspective view; 
           [0008]      FIG. 5  is a cross-sectional view taken along lines  5 - 5  in  FIG. 3 ; 
           [0009]      FIG. 6  is a perspective view of the latch assembly as viewed from below showing the bolt rotated relative to the brackets; 
           [0010]      FIG. 7  is an enlarged elevational view of the cam removed from the latch assembly showing the extending finger portion and the curved generally angled groove of the locking cam of the latching mechanism; 
           [0011]      FIG. 8  is a cross-sectional view taken along lines  8 - 8  in  FIG. 7  showing the locked and unlocked positions of the locking cam; and 
           [0012]      FIG. 9  is a perspective view of the latch assembly as shown in  FIG. 1  installed in a structure, as viewed from below the structure. 
       
    
    
       [0013]    The exemplification set out herein illustrates embodiments of the disclosure that is not to be construed as limiting the scope of the disclosure in any manner. Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
       DETAILED DESCRIPTION 
       [0014]    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, embodiments with the understanding that the present description is to be considered an exemplification of the principles of the disclosure and is not intended to be exhaustive or to limit the disclosure to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. 
         [0015]    As shown in  FIGS. 1 and 9 , disclosed is a latch mechanism  20  configured for latching a first member  24  to a second member  28  in a structure such as might be used on an aircraft structure. The latch mechanism  20  includes a pair of brackets  32 ,  34  for attaching the latch  20  to the first member  24 . A bolt assembly  40  is pivotally carried on a pin  44  and bushing  48  secured to and extending between the bracket portions  32 ,  34 . As shown in  FIG. 2  and with reference to  FIGS. 1 and 9 , the assembly can pivot about the pin  44  to allow disengagement of the first member  24  from the second member  28 , to which the assembly is secured by the brackets  32 ,  34 . 
         [0016]    With reference to  FIGS. 1-9 , a trigger  50  is carried on the bolt  40  by means of pin  54  extending through the trigger and bushing  58 . A second pin  60  extends through the trigger  50  to retain the biasing spring  64  in association with the trigger  50  and acting against the bolt  40 . Additional pins  66 ,  68 , are engaged on and extend between the brackets  32 , 34 . Pin  66  is positioned for engagement by the hook ends  70  of the trigger  50 . Pin  68  extends through a biasing spring  74  which is retained on downwardly extending portions  76 ,  78  of the brackets  32 , 34  to which the pin  68  is attached. The spring  74  biases against the bolt  40  to urge the bolt  40  in an upward or open position. 
         [0017]    With reference to the Figures, a generally cylindrical locking cam  80  is carried on the bolt  40 , extending through a bore  84  in the bolt  40 . The cam  80  is retained in the bore  84  by interference engagement of the bushing  58  and the corresponding groove or notch  130  on the body of the cam  80 . A return spring  94  is positioned around an upper portion  98  of the cam  80  with a first end attached to the upper portion  98  of the cam  80 . A second end is attached to the bolt  40  to provide an axial rotary return. 
         [0018]    The upper portion  98  of the cam  80  extends from the bore  84  and a corresponding opening  100  on the trigger  50 . This allows access by a tool to the drive opening  102  in the cam which is generally flush with the surface of the trigger  50 . Engagement of the cam head drive opening  102  with a tool allows the cam  80  to be rotated thereby locking or unlocking an extending finger  104  of the cam with the pin  66 . This locking feature  79 , including cam  80  integrated in the bolt  40  and the corresponding pin  66 , prevents the latch  20  from being opened or closed without a tool engaged in the drive opening  102 . This makes the latching mechanism more resistant to tampering and human error (leaving the latch unlocked) than prior designs. 
         [0019]    In use, the assembled latch mechanism  20  is retained on the first member  24 . This provides a latching action of the extending portion  110  of the bolt  40  and the adjustable threaded stop portion  112  attached thereto against the second portion  28 . In other words, in the closed latch configuration, see  FIGS. 1 ,  5  and  9 , the primary portion  114  of the latch is attached is to the first member  24  with the extending portion  110  and adjustable body  112  engaging a corresponding underside of the second member  28 . The extending portion  122  of the brackets  32 ,  34  provide attachment sites to attach the brackets  32 , 34  to the first portion  24 .  FIGS. 1 ,  5  and  9  show the closed, locked configuration with the trigger  50  engaging an extending lip  124  of the bolt. Protruding portions  128  of the trigger engaged underneath the lip  124 . Even if the trigger is actuated, the latch will not open unless the cam  80  is rotated with a tool to the “unlocked” position. When the cam  80  is rotated to the unlocked position the latch will not open unless the trigger is actuated to disengage the hooks  70  from the pin  66 . The drive opening  102  end of the cam  80  extends through the opening  100  and a corresponding opening  22  on the bolt. 
         [0020]    As shown in  FIG. 6 , the bolt  40  has been rotated about the pin  44  relative to the brackets  32 ,  34 . As shown in this view, the extending or protruding finger  104  is shown in the “locking” position. The locking position orients the finger  104  towards the pin  66 . It should be noted that the cam  80  is rotated  90 ° to unlock the bolt from the pin  66 . Also, shown in  FIG. 6  is the engagement of the protruding portion  128  of the trigger  50  engaged underneath the edge of the lip  124 . 
         [0021]    Turning to  FIG. 7 , shown is an enlarged elevational view showing the extending finger portion  104  and the curved, generally angled groove  130  of the locking cam  30  of the latching mechanism  20 . This view shows the protruding or extending finger portion  104  of the locking cam  80 . Also shown is an angular groove  130 . The angular groove  130  includes a locked portion  134  and an unlocked portion  136 . With reference to  FIG. 4  the bearing  58  engages the groove  130 . Throughout the generally right angle rotation of the cam  80  the bearing  58  will either engage the locked portion  34  with the finger  104  extending generally parallel to the longitudinal axis of the bolt  40  or along the unlocked portion  136  in which the finger is rotated generally 90° resulting in a generally perpendicular orientation relative to the longitudinal axis of the bolt  40 . As shown, a leading edge  140  of the finger  104  is provided with a curved edge. This curved edge helps to facilitate engagement of the finger underneath the pin  66 . Similarly, an internal elbow  142  of the finger  104  is provided with a curved edge. 
         [0022]    The latch mechanism  20  helps to secure two bodies  24 ,  28  such as a door or a hatch on an aircraft. The latch mechanism  20  requires a tool such as by engagement with the drive opening  102  in the cam  80 . The cam  80  provides a locking feature by way of engagement of the finger  104  with the bushing  48  carried by the pin  44  extending through the portions  78 ,  76  of the brackets  34 ,  32 . Indicia in the form of the word “unlocked”  150  and “locked”  152  are provided on the latch surface including an indicator  154  to indicate whether the latch is in the “locked” ( 152 ) or “unlocked” ( 150 ) positions. The indicator  154  aligning with the indicated position,  152 ,  150 . The indicia and the positively oriented locking feature  104 ,  48  prevent a “false positive” indication that might otherwise lead a ground crew to wrongly assume the latch on the aircraft is secure and ready for flight. The relatively continuous bolt  40  provides significant strength in the assembly with minimal mechanical elements while minimizing weight associated with the latch mechanism  20 . 
         [0023]    In use, to release the latch  20 , a tool must be inserted into the drive opening  102  of the cam  80  and rotated a ¼ turn. The trigger  50  must then be depressed to cause disengagement of the hook  70  from the pin  66 . These actions release or disengage the bolt  40  from the locked position. Once unlocked, the bolt  40  can be pivoted about pin or pivot point  44  (see rotation illustrated in  FIG. 2 ) to the position shown in  FIG. 6 . This rotation disengages the adjustable stop  112  from the door frame or second member  28 . It should be noted that the cam  80  is spring loaded by means of the spring  94 . One end of the spring  94  engages the bore  84  with another end of the spring engaging the upper portion  98  of the cam  80 . 
         [0024]    The coil spring  94  attached to the latching mechanism as described is configured to spring load the cam in the “locked” position. Spring loading the cam in a locked position helps maintain the latch in the locked position against vibration and causes the cam  80  to rotate the finger  104  generally parallel to the longitudinal axis of the bolt  40  even when the latch is opened. This provides a safety which causes the finger  104  of the cam  80  to balk against the pin  66  and indicate an open latch condition. The ground crew must then properly orient the cam  80  to engage the finger  104  underneath the pin  66  using a tool and returning the cam to the “locked”  152  position. Additionally, the bolt  40 , at least in the area of the cam  80 , can be color coordinated to provide a flag so that a prominent color is displayed when the cam  80  balks against the pin  66 . This color coordination provides an additional indicator to the ground crew that the latch  20  must be completely closed. Also, in the unlatched position the hook  70  of the trigger  50  will ride on top of the pin  66  to further indicate a disengaged or unlocked position. 
         [0025]    While this disclosure has been described as having an exemplary embodiment, this application is intended to cover any variations, uses, or adaptations using its general principles. It is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the spirit and scope of the disclosure as recited in the following claims. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice within the art to which it pertains.