Abstract:
A latch mechanism for use in attaching portions or panels on an aircraft. The latch mechanism and related method include a detent mechanism for releasably coupling a bolt portion of the latch to a handle portion of the latch. The latch allows the bolt and handle to conjointly pivot with respect to a corresponding mounting bracket. The latch operates to relieve pressure in an excess pressure condition when the forces associated with the detention mechanism are overcome.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. provisional patent application No. 61/266,803, filed Dec. 4, 2009, the disclosure of which is herein incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a pressure relief latch mechanism for releasably latching and/or holding a first member with respect to a second member, and in particular to a latch mechanism including a manually operable trigger for releasing a bolt of the latch mechanism from a latched condition and that is configured to alternatively automatically release the bolt of latch mechanism from the latched condition in response to an over-pressure condition encountered by the first member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0003]      FIG. 1  is a perspective view of the latch mechanism shown in the latched condition. 
           [0004]      FIG. 2  is a partial cross sectional view of the latch mechanism shown in the latched condition and releasably latching a first member to a second member. 
           [0005]      FIG. 3  is a broken-away side elevational view of the latch mechanism shown in the latched condition. 
           [0006]      FIG. 4  is a top plan view of the latch mechanism shown in the latched condition. 
           [0007]      FIG. 5  is a bottom view of the latch mechanism shown in the latched condition. 
           [0008]      FIG. 6  is a left end view of the latch mechanism shown in the latched condition. 
           [0009]      FIG. 7  is a right end view of the latch mechanism shown in the latched condition. 
           [0010]      FIG. 8  is a side cross sectional view of the latch mechanism shown in the latch condition with the mounting bracket removed. 
           [0011]      FIG. 9  is a top perspective view of the latch mechanism shown in the latched condition with the handle removed. 
           [0012]      FIG. 10  is a bottom perspective view of the latch mechanism shown in the latched condition with the mounting bracket removed. 
           [0013]      FIG. 11  is a perspective partial cross section view of the handle of the latch mechanism. 
           [0014]      FIG. 12  is a partial view of the latch mechanism showing the trigger, bolt and detent mechanism in the latched condition. 
           [0015]      FIG. 13  is a top view of the trigger, bolt and detent mechanism as shown in the latched condition with the handle and mounting bracket removed. 
           [0016]      FIG. 14  is a bottom view of the trigger, bolt and detent mechanism shown in the latched condition with the handle and mounting bracket removed. 
           [0017]      FIG. 15  is a partially exploded view of the latch mechanism. 
           [0018]      FIG. 16  is a side elevational view of the latch mechanism showing the trigger pivoted toward an extended position and the latch mechanism in an unlatched condition. 
           [0019]      FIG. 17  is a side elevational view of the latch mechanism shown in an unlatched condition with the bolt, handle and trigger in extended positions. 
           [0020]      FIG. 18  is a perspective view of the latch mechanism showing the bolt pivoted to an extended position in response to an over-pressure condition such that the latch mechanism is in the unlatched condition while the handle and trigger are in the retracted position. 
           [0021]      FIG. 19  is a side elevational view of the latch mechanism shown in  FIG. 18  with the bolt in the extended position and the trigger and handle in the retracted position such that the latch mechanism is in the unlatched condition. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    As shown in the drawing figures, latch mechanism  20  is adapted to releasably latch a first member  22  to a second member  24 . First member  22  includes a first surface  26 , a second surface  28  and an aperture  30  that extends through first member  22  from first surface  26  to second surface  28 . Second member  24  includes a first surface  32  and a second surface  34 . Second member  24  may be, for example, an aircraft frame or other body member. First member  22  may be, for example, a door or panel that is adapted to be removed or displaced with respect to second member  24 . 
         [0023]    Latch mechanism  20  includes a mounting bracket  40  that extends between a first end  42  and a second end  44 . Bracket  40  includes a pair of generally planar side walls  46  that are spaced apart and generally parallel to one another. A generally planar bottom wall  48  extends between the bottom ends of side walls  46  and is generally perpendicular to side walls  46 , such that the side walls  46  and bottom wall  48  are generally U-shaped and form an open receptacle therebetween. A flange  50  extends outwardly and generally perpendicularly from the top end of each side wall  46 . Each flange  50  includes one or more apertures adapted to receive a fastener for use in attaching bracket  40  in engagement with the second surface  28  of the first member  22  in alignment with aperture  30 . 
         [0024]    Latch mechanism  20  includes a bolt  56  pivotally coupled to bracket  40  by a pin  58  having a generally linear central axis  60 . Pin  58  extends generally transversely between side walls  46  of mounting bracket  40  and is coupled at each end to a respective side wall  46 . As shown in  FIG. 2 , bolt  56  is in a retracted position with respect to bracket  40  such that latch mechanism  20  is in a latched condition whereby latch mechanism  20  releasably latches first member  22  to second member  24 . Bolt  56  is pivotal with respect to bracket  40  about axis  60  from the retracted position as shown in  FIG. 2  toward an extended position as shown in  FIGS. 17-19 , wherein latch mechanism  20  is in the unlatched condition and first member  22  may be removed from, or displaced with respect to, second member  24 . Bolt  56  includes an engagement member  62  that is located longitudinally outwardly from second end  44  of mounting bracket  40 , such that engagement member  62  is adapted to engage second surface  34  of second member  24  when bolt  56  is in the retracted position and latch mechanism  20  is in the latched condition. Bolt  56  also includes an arm  64  extending between a first end  66  and a second end  68 . Arm  64  and engagement member  62  are located on opposite sides of pin  58  and axis  60 . Arm  64  includes a convexly curved outer surface  70  that extends between first end  66  and second end  68 . A recess or detent  72  is formed in outer surface  70  adjacent second end  68  of arm  64 . Outer surface  70  of arm  64  conforms generally to an arc of a circle about axis  60  between second end  68  of arm  64  and detent  72 . 
         [0025]    Latch mechanism  20  includes an elongate handle  78  that extends between a first end  80  and a second end  82 . Handle  78  includes a pair of generally planar side walls  84  that are spaced apart and generally parallel to one another. A generally planar top wall  86  extends between the top ends of side walls  84  generally perpendicular to side walls  84 , such that side walls  84  and top wall  86  are arranged in a generally inverted U-shaped manner. Top wall  86  includes an aperture  88  configured to receive arm  64  of bolt  56 . As shown in  FIG. 11 , handle  78  includes an internal wall  90  located between first end  80  and second end  82  and that extends generally perpendicular to side walls  84  and top wall  86 . Internal wall  90  includes a central generally circular aperture  92 . Handle  78  includes a bottom wall  94  that extends between first end  80  and internal wall  90 , and between the bottom ends of side walls  84 . An elongate generally cylindrical chamber  96  is formed in handle  78  between side walls  84 , top wall  86  and bottom wall  94  that extends from first end  80  to internal wall  90 . Aperture  92  is in communication with chamber  96 . Bottom wall  94  includes an aperture  98  that is communication with chamber  96 . 
         [0026]    Side walls  84  of handle  78  include an aperture  100  at second end  82 . Side walls  84  of handle  78  are located between side walls  46  of mounting bracket  40  with bolt  56  located between side walls  84  of handle  78 . Pin  58  extends through apertures  100  of side walls  84  of handle  78  such that handle  78  is pivotally coupled to mounting bracket  48 . Handle  78  is pivotal with respect to mounting bracket  40  about axis  60  between a retracted position as shown in  FIG. 1 , and an extended position as shown in  FIG. 17  wherein latch mechanism  20  is in an unlatched condition. A resilient biasing member, such as a torsion spring or a leaf spring, is coupled to handle  78  and resiliently biases handle  78  toward the extended position. 
         [0027]    Handle  78  includes one or more retention members  104  at first end  80 . A retention member  104  may be respectively located at each side wall  84 . Each retention member  104  includes a generally planar top engagement surface  106  and a biasing surface  108  at the outer distal end of the retention member  104 . Biasing surface  108  may be generally planar and inclined with respect to a central longitudinal axis  110  of handle  78  or biasing surface  108  may be curved. 
         [0028]    Latch mechanism  20  includes a detent mechanism  114  located within chamber  96  of handle  78 . Detent mechanism  114  includes a detent member  116  such as a generally spherical metal ball or cylindrical roller. Detent mechanism  114  includes an adjustable biasing mechanism  118  having a resilient biasing member  120 , such as a helical coil spring, a plunger  122  and a plug or base member  124 . Biasing member  120  extends between a first end  126  and a second end  128  generally concentrically about axis  110 . Plunger  120  includes a head  130  having a recess  132  configured to receive a portion of detent member  116 . Plunger  120  also includes a generally cylindrical stem extending from head  130  along axis  110 . Stem  134  extends within second end  128  of biasing member  124 . Base member  124  includes a head  138  and a stem  140  that extends within first end  126  of biasing member  120 . 
         [0029]    First end  126  of biasing member  124  engages an interior surface of head  138  of base member  124 , and second end  128  of biasing member  120  engages an interior surface of head  130  of plunger  122 . Biasing member  120  resiliently biases plunger  122  into engagement with detent member  116  and thereby resiliently biases detent member  116  toward internal wall  90  of handle  78  and into detent  72  of bolt  56  as shown in  FIG. 8 . The outer circumferential surface of head  138  of base member  124  threadably engages threads in cylindrical chamber  96  such that selective rotation of base member  124  about axis  110  will move base member  124  along axis  110  in a desired direction to compress or expand biasing member  120  to a desired extent such that biasing member  120  applies a desired force to detent member  116  for engagement with detent  72 . 
         [0030]    When detent member  116  is in an extended position as shown in  FIG. 8 , a portion of detent member  116  projects outwardly from aperture  92  of internal wall  90  and is located within detent  72  of arm  64  of bolt  56  to inhibit pivotal movement of belt  56  with respect to handle  74 . Detent member  116  thereby releasably locks bolt  56  to handle  78  such that bolt  56  and handle  78  will conjointly pivot with one another about axis  60 . However, when a sufficiently large force as applied to engagement member  62  of bolt  56  in a generally downward direction is viewed in  FIG. 8 , the retention force with which biasing member  120  presses detent member  116  into detent  72  of bolt  56  may be overcome, such that arm  64  of bolt  56  presses detent member  116  toward base member  124  and first end  80  of handle  78  along axis  110  and compresses biasing member  122 , such that bolt  56  may rotate in a generally clockwise direction about axis  60  with respect to handle  78  and bracket  40 . When detent member  116  is no longer located within detent  72 , bolt  56  may pivot about axis  60  with respect to mounting bracket  40  and handle  78  to a retracted position as shown in  FIGS. 18-19 . Outer surface  70  of arm  64  slides along detent member  116  as bolt  56  pivots about axis  60  between the retracted position as shown in  FIG. 8  and the extended position as shown in  FIG. 18 . Bolt  56  may be manually returned to the position as shown in  FIG. 8  with respect to handle  78  by pressing downwardly on second end  68  of arm  64  to pivot bolt  56  in a counter-clockwise direction about axis  60  with respect to handle  78  until detent member  116  is located within detent  72  of bolt  56 . 
         [0031]    Latch mechanism  20  also includes a trigger  150  that extends between a first end  152  and a second end  154 . Trigger  150  includes a body  156  and an arm  158  that extends downwardly from the bottom end of body  156 . A distal end of arm  158  includes a bore  160 . A pin  162  having a central axis  164  extends through bore  160 . The ends of pin  162  are coupled to respective side walls  46  of mounting bracket  40 . Trigger  150  is located between side walls  46  of mounting bracket  40  and is pivotally coupled to mounting bracket  40  by pin  162  such that trigger  150  is pivotal with respect to mounting bracket  40  about axis  164 . Axis  164  is spaced apart from and generally parallel to axis  58  of pin  60 . Body  156  of trigger  150  includes an inclined slot  166  that is open at the top surface of body  156 . Slot  166  is adapted to receive a tool, such as the tip of the screw driver, to assist in manually pivoting trigger  150  from a retracted position as shown in  FIGS. 1 and 8  in a counter-clockwise direction about axis  164  to an extended position as shown in  FIGS. 16 and 17 . Body  156  of trigger  150  includes a locking member  170  having a bottom surface  172  adapted to engage engagement surface  106  of retention members  104  of handle  78  when handle  78  is in the retracted position and trigger  150  is in the retracted position as shown in  FIGS. 3 and 8 , such that locking member  170  prevents pivotal movement of handle  78  about axis  68  in a generally clockwise direction with respect to mounting bracket  40  when a force is applied to engagement member  62  of bolt  56 . 
         [0032]    Latch mechanism  20  includes a resilient biasing member  180 , such as coil torsion spring. A pin  182  extends between and is coupled to side walls  46  of mounting bracket  40  and couples biasing member  180  to bracket  40 . Biasing member  180  includes a first end  184  that is in biased engagement with a bottom surface of body  156  adjacent first end  152  of trigger  150  and a second end  186  that is in biased engagement with bottom wall  48  of mounting bracket  40 . Biasing member  180  may be wrapped around pin  182 . Biasing member  180  resiliently biases trigger  158  in a generally clock-wise direction about axis  164  from the extended position of trigger  150  as shown in  FIGS. 16 and 17  toward the retracted position of trigger  150  as shown in  FIG. 3 . Trigger  150  is selectively manually pivotal from the retracted position as shown in  FIGS. 3 and 8 , wherein trigger  150  locks handle  178  in the retracted position with respect to mounting bracket  40 , toward an extended position as shown in  FIGS. 16 and 17  wherein locking member  170  of trigger  150  is released from retention members  104  of handle  78 , such that handle  78  and bolt  56  may conjointly pivot about axis  60  from their retracted positions toward their extended positions whereupon bolt  56  is released from second member  24 . First member  22  may then be removed from, or repositioned with respect to, second member  24 . 
         [0033]    When trigger  150  is manually released, the biasing member  180  will resiliently bias trigger  150  from the extended position to the retracted position. When the handle  178  and bolt  56  are in the extended positions, the handle  78  and bolt  56  may be manually pivoted in a generally counter-clockwise direction about axis  60  by manually pressing second end  80  of handle  78  toward the retracted position. As handle  78  is pivoted toward the retracted position, biasing surfaces  108  of retention members  104  will engage second end  154  of trigger  150  and will pivot trigger  150  in a counter-clockwise direction about axis  164  until retention members  104  pass by locking member  170  of trigger  150 . Biasing member  180  then pivots trigger  150  in a clockwise direction about axis  162  such that locking member  170  of trigger  150  engages retention members  104  of handle  78  to thereby releasably lock handle  74  in the retracted position. 
         [0034]    In the event an excess-pressure condition is encountered, wherein an excess pressure above a predetermined pressure is applied to second surface  28  of first member  22 , which results in a predetermined excess force being applied to engagement member  62  of bolt  56 , the excess force will overcome the force with which detent member  116  engages arm  64  of bolt  56  such that the arm  64  of bolt  56  will move detent member  116  along axis  110  in a direction away from bolt  56  and toward base member  124 . Bolt  56  will then automatically pivot in a generally clock-wise direction about axis  60  with respect to handle  78  and mounting bracket  40  toward an extended position as shown in  FIGS. 18 and 19  whereby engagement member  62  is released from second member  24 . Arm  64  of bolt  56  will extend and pass through aperture  88  in top wall  86  of handle  78  as bolt  56  pivots in a clockwise direction about axis  60  with respect to handle  78 . First member  22  may be automatically removed from, or repositioned with respect to, second member  24  as a result of the excess-pressure condition, thereby preventing or reducing damage that may otherwise be caused to first member  22  and second member  24 . Bolt  56  may be manually reset to the retracted position with respect to handle  78  as shown in  FIG. 8  by pressing downwardly on second end  68  of arm  64 . 
         [0035]    Various features of the invention have been particularly shown and described in connection with the illustrated embodiment of the invention, however, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest interpretation within the terms of the appended claims.