Patent Publication Number: US-7712801-B2

Title: Rotary pawl latch

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of the priority of United States Provisional Application for patent Ser. No. 60/838,250, filed on Aug. 16, 2006, the entirety of which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to the field of latches. 
   2. Brief Description of the Related Art 
   Latches are relied on in many applications for securing, for example, doors in a closed position. Although many latches are known in the prior art, none are seen to teach or suggest the unique features of the present invention or to achieve the advantages of the present invention. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a rotary pawl latch that has a lock bar that engages with the pawl when the pawl is latched and that moves toward the axis of rotation of the pawl to release the pawl for unlatching. This lock bar never completely becomes disengaged from the envelope of the pawl. There are cutouts in the pawl which allow the pawl to rotate as the lock bar is actuated. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1-62  are views of a first embodiment of a rotary pawl latch according to the present invention. 
       FIGS. 63-128  are views of a second embodiment of a rotary pawl latch according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Two embodiments  100  and  300  have been designed. Both utilize the same basic new pawl mechanism, which has a lock bar engaged with the pawl when latched that moves toward the center of the pawl to release the pawl for unlatching. This lock bar never completely becomes disengaged from the envelope of the pawl. There are cutouts in the pawl which allow the pawl to rotate as the lock bar is actuated. As can be readily seen in  FIGS. 9 ,  10 ,  27 ,  28 ,  37 ,  38 ,  52 ,  53 ,  55 ,  56 ,  77 - 80 ,  91 - 95 ,  97 - 98 , and  100 - 101 , the lock bar  110 ,  310  is positioned to extend through the lock bar slot  124  of the pawl, also referred to as a cutout, at all times during operation of the rotary pawl latch. A step of the pawl that is engaged by the lock bar to keep the pawl in the latched position is formed by the inner profile of the lock bar slot. Both embodiments use a push button user interface to actuate the lock bar. The main advantage realized with this new pawl release mechanism is the ability to have a compact package space for the pawl and lock bar, which in turn enables the whole latch to be made smaller than prior rotating pawl glove box latches. One difference between both embodiments is the direction the striker moves with respect to the latch, and correspondingly the orientation of the rotating pawl within the latch. Another slight difference is in the cutouts of the pawl. In embodiment  100  the pawl does not completely rotate to the open position when the button is fully depressed so that the striker does not fully become free of the pawl until the button is released. In embodiment  300 , the pawl does completely rotate when the button is fully depressed. The differences in geometry of the cutout or lock bar slot results from the desire to make the pawl as strong as possible by minimizing the cutout area in the pawl of embodiment  100 . Another difference between the two embodiments is in how the push button operates. The embodiment  100  is a relatively simple version that has two plunger legs under the button and rides on two cylindrical compression springs. The button is trapped by fasteners on the far ends of the plunger legs. O-rings on the plungers cushion the button as its stroke bottoms out in both depressed and extended positions. In the embodiment  300 , the button rides on two torsion springs to help minimize stroke noise. Additionally, it also has long bayonet legs to help guide the button from cocking as it is depressed. Further, it also has living spring leg features around the top periphery of the button to help keep the top of the button centered within the housing. The pawl mechanism common to the two embodiments can be used in combination with a variety of mechanisms for actuating the lock bar, as evidenced by the two exemplary embodiments  100  and  300 . The pawl mechanism may also be used with a lift handle for actuation, and such a combination is contemplated as being within the scope of the present invention. 
   The First Embodiment 
   The embodiment  100  of the Rotary Pawl Latch consists of a housing  102 , a button  104  with integrated guide rails  118 , a pawl  106 , a Pawl Torsion Spring  108 , a Lock bar  110 , one or more Button Compression Springs  112 , O-rings  114 ,  136  or Grommet bumpers (not shown), and one or more Push studs  116 . 
   In assembly, the Pawl Torsion Spring  108  is assembled around the Pawl posts  120  and this subassembly is then snapped into the Housing  102 . The Lock bar  110  can then be slid in from the side of the housing  102  and through both the central tower  122  of the housing and the lock bar slot  124  of the Pawl  106 . The button  104  along with the button springs  112  are installed in the housing  102  with the integrated guide rails  118  providing some constraint in both location and movement of the button  104 . O-rings  114 ,  136  are situated on the centerline guide posts  126  of the Button  104  that extend through bores  128  in the housing  102 . Push studs  116  are installed into the Button guide posts  126  to keep the entire assembly together. Alternatively, designs can be made using a set of grommets installed into the housing  102  in lieu of the O-rings  114 ,  136  on the button  104 , and variations exist using snap in features in lieu of the push studs  116 . 
   In the “latched” position (e.g. shown in  FIG. 10 ), the pawl torsion spring  108  biases the pawl  106  toward the unlatched position (e.g. shown in  FIG. 28 ) and forces the pawl  106  against the lock bar  110 , and the striker  130  is fully constrained between the throat  132  of the pawl  106  and the housing tower  122 . The lock bar  110  in turn is held in double shear against the central tower  122  of the housing  102  and the stepped portion  134  of the pawl  106 . The button  104  is biased by springs  112  to the outward-most position (e.g. shown in  FIG. 27 ) with the O-rings  114  bottoming out on the housing  102  to maintain the position of the button  104 . The center ribs  138  of the button  104  are positioned just adjacent the lock bar  110  and are almost in contact with it as e.g. illustrated in  FIGS. 9 and 10 . The lock bar  110  is positioned generally intermediate the center ribs  138  and the axis of rotation of the pawl  106  defined by pawl posts  120 . The pawl spring  108  also has a loop  140  that engages the pawl  106  on one side of the opening of the throat  132  of the pawl  106  to bias the pawl  106  toward the unlatched position. The loop  140  also extends along a portion of the throat  132  of the pawl  106  to put some preload on the striker  130 . This helps reduce the Buzz, Squeak, and Rattle issues related to the striker/pawl interface. 
   In operation, the button  104  is depressed to the depressed position (e.g. illustrated in  FIGS. 38 and 37 ) into the body of the housing  102 . As the button  104  travels rectilinearly inward relative to the housing  102 , the integrated guides  118 ,  126  of the button  104  act to stabilize the movement of the button and the two center ribs  138  begin to act on the lock bar  110 . Continuing to press the button  104  causes the center ribs  138  to flex the lock bar  110  (the lock bar  110  is a living spring design with its natural unloaded state in the “latched” position illustrated e.g. in  FIGS. 9 and 10 ) towards the center, i.e. axis of rotation, of the pawl  106 . As the lock bar  110  moves toward the center of the pawl  106 , the torsion spring load on the pawl  106  acts to try and move the pawl  106  to the unlatched position illustrated e.g. in  FIG. 28 . Once the button  104  is moved far enough inward of the housing  102 , the lock bar  110  moves out of engagement with the step  134  in the pawl  106 , as shown in  FIG. 38 , and the pawl  106  can begin to rotate to the unlatched position under the bias of torsion spring  108 . This allows the striker  130  to be released and the door  142  to be opened as shown in  FIGS. 28 and 29 . Continuing to depress the button  104  will cause the internal O-rings  136  to impact against the other side of the housing  102  in relation to O-rings  114 . This helps reduce the noise of operation. As long at the button  104  is fully depressed, the pawl  106  does not fully open but is set to move and remain in the unlatched position upon release of the button  104 . When the button  104  is released, the pawl  106  can finish rotating to the unlatched position and the button  104  returns to its outward-most position dead-stopping the O-rings  114  against the housing  102  to again reduce operational noise. With the pawl  106  in the unlatched position and the button  104  released, the lock bar  110  is allowed to relax and return to its natural unloaded state, illustrated in  FIGS. 9 ,  10 ,  27 , and  28 , by virtue of the shape of the inner cam profile  144  of the lock bar slot  124  of the pawl  106 . 
   In latching, the striker  130  is bought into to position to the pawl throat  132  and begins to rotate the pawl  106  back in to the latched position as the door  142  is moved to the closed position illustrated in  FIG. 11 . As the pawl  106  rotates, the inner cam profile  144  of the pawl  106  flexes the lock bar  110  back toward the center of pawl  106  until it can spring back behind and into engagement with the step  134  in order to secure and maintain the pawl  106 , the striker  130  and the door  142  in their latched or closed positions. The button  104  does not move during this operation. The striker  130  is again constrained by the pawl  106  and housing tower  122 . 
   Note, an alternative design uses grommets installed in the housing  102  in lieu of the O-rings  114 ,  136  on the button  104 , Functionally, it is very similar except that the hard points are now on the button  104  rather than the housing  102 . On opening, the button  104  would impact on the grommet to reduce noise and on closing the Push studs  116  in the button  104  would dead-stop against the grommet. 
   The Second Embodiment 
   Operation of embodiment  300  is very similar to that of embodiment  100 . Pressing the button  304  flexes the lock bar  310  towards the center, i.e. the axis of rotation, of the pawl  306  allowing the pawl  306  to move to the unlatched position. The major differences between the latch  300  and the latch  100  are around alignment features and spring usage. The latch  300  has a larger contact area internally to help guide the button  304  more linearly and side “living” springs  346  are included on the button carrier  348  to better constrain and center the button face plate  350  within the housing  302 . 
   The latch  300  also makes use of torsion springs  312  internally in lieu of the compression springs  112  of the latch  100 . This was done to help alleviate potential noise issues. There are no sound-deadening features present on the latch  300 . 
   The latch  300  incorporates improvements in the alignment features by increasing the side arms  318 ,  326  on the button carrier  348  and introducing “living” springs  346  on the side of the carrier  348  to better center the button  304  in the housing  302 . The compression springs  112  in the button area were replaced with torsion springs  312  to limit noise issues. The button  304  was also made in two pieces, a carrier  348  and a face plate  350 , to provide for more control/variation of the geometry and the aesthetic design of the face plate while still being able to use the same internal parts for the button  304 . This reduces the tooling costs involved in changes in the aesthetic design of the face plate  350 . 
   The pawl throat  332  was also rotated relative to the pawl throat  132  of the latch  100  to reorient the direction of rectilinear motion of the button  304  relative to the direction of the relative motion of the striker  130 ,  330  upon opening of the door  142 ,  342  depending upon application requirements. The function remains similar in that the lock bar  310  is internal to the pawl  306  and releases the pawl  306  by moving or flexing towards the center of the pawl  306 . 
   The present invention is not limited to the embodiments described above, but is understood to encompass all embodiments within the scope of the appended claims and their equivalents.