Abstract:
A latch and a method for preventing a latch from failing to open while a connected handle is lifted are provided. The latch includes a primary pawl pivotally mounted to the latch. An end piece having a protrusion extending from it is fixed to the primary pawl. An inner lever is rotatably coupled to the end piece. The inner lever includes a tail adjacent the protrusion of the end piece. The inner lever is movable between a first position and a second position. A secondary pawl is pivotally mounted to the latch and is movable between a first position and a second position. A blocking lever is also coupled to the latch and movable between a first position and a second position. When the inner lever is in a second position, the tail abuts the protrusion and the blocking lever limits movement of the inner lever and the primary pawl.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/625,156 filed Apr. 17, 2012, the entire contents of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Exemplary embodiments of the present invention relate generally to latches and, more particularly, to latches for vehicles. 
     Conventional latches commonly include an electrical reset mechanism for disengaging a pawl from a claw to allow the claw to rotate to an open position and release a striker. If the motor stops before a lifted door handle connected to the latch is released, the pawl will bias back into engagement with the claw before the claw has rotated to an open position. This early release of the pawl while the handle is still lifted results in the pawl engaging the claw in a partially opened or safety position. In this circumstance, the release of the pawl is not properly timed and therefore the pawl creates undesirable noise as it contacts the surface of the claw before reaching the safety position. 
     Accordingly, while existing vehicle latch mechanisms are suitable, the need for improvement remains, particularly in providing a latch having a mechanism that prevents the pawl from prematurely engaging the claw while a door is lifted. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment, a latch is provided. The latch having a claw rotatably mounted to the latch for movement between a latched position and an unlatched positon; a primary pawl configured to engage the claw when the claw is in the latched position so that the claw is retained in the latched position and disengage the claw so that the claw can rotate to the unlatched position from the latched position; an inner lever movably mounted to the latch for movement between a first position of the inner lever and a second position of the inner lever, wherein the inner lever prevents the primary pawl from engaging the claw when the inner lever is in the second position; a secondary pawl rotatable between a first position of the secondary pawl and a second position of the secondary pawl, wherein movement of the inner lever from the first position of the inner lever to the second position of the inner lever is prevented by the secondary pawl when the secondary pawl is in the first position of the secondary pawl and wherein movement of the inner lever from the second position of the inner lever to the first position of the inner lever is prevented when the secondary pawl is in the second position of the secondary pawl; a handle operatively connected to the secondary pawl, wherein movement of the handle causes the secondary pawl to rotate between its first and second positions; a motor operatively coupled to the primary pawl, wherein actuation of the motor causes the primary pawl to disengage the claw so that the claw can rotate to the unlatched position from the latched position; and a blocking lever movable between a first position of the blocking lever, wherein the blocking lever allows the inner lever to move from the first position of the inner lever to the second position of the inner lever and a second position of the blocking lever, wherein the blocking lever contacts a portion of the inner lever when the inner lever is in the second position and prevents movement of the inner lever from the second position of the inner lever to the first position of the inner lever, wherein movement of the secondary pawl from the first position of the secondary pawl to the second position of the secondary pawl causes movement of the blocking lever from the first position of the blocking lever to the second position of the blocking lever. 
     According to another embodiment of the present invention, a method is provided for preventing a primary pawl of a latch from engaging a claw of the latch when a handle is lifted, the method including the steps of: rotating a secondary pawl from a first position of the secondary pawl to a second position of the secondary pawl when the handle is lifted; disengaging the primary pawl from the claw via operation of a motor when the handle is lifted; allowing an inner lever to move from a first position of the inner lever to a second position of the inner lever when the handle is lifted; and retaining the inner lever in the second position with a blocking member that rotates from a first position to a second position as the secondary pawl rotates from the first position of the secondary pawl to the second position of the secondary pawl, wherein the inner lever prevents the primary pawl from engaging the claw when the inner lever is in the second position. 
     The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  is a side view of a door latch according to an embodiment of the invention; 
         FIG. 2  is a side view of a door latch according to an embodiment of the invention; and 
         FIG. 3  is a side view of a door latch according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the FIGS., an exemplary latch  20  is illustrated. This latch  20  may be integrated into a component of a vehicle, such as the vehicle door, trunk, frame surrounding the door opening or trunk opening or any other operable component for example. The latch  20  includes a claw  30  and a cooperating primary pawl  50 . The claw  30  is pivotally mounted by a stud positioned in hole  32  and the pawl  50  is pivotally mounted by stud  52 . In an exemplary embodiment, the claw  30  is biased in the direction indicated by arrow A, such as by a torsion spring (not shown) for example, and the primary pawl  50  is biased in the direction indicated by arrow B into engagement with the claw  30  by the spring  22 . The claw  30  has a slot or throat  34  for receiving and retaining a striker (not shown) located on a complementary vehicle component. In an exemplary embodiment, the claw  30  includes at least a primary shoulder  36 . The primary pawl  50  includes a first leg  54  that positively engages the primary shoulder  36  of the claw  30  to hold the claw  30  against a biasing force in a latched position. 
     When the claw  30  rotates between an unlatched and a latched position, a portion  40  of the claw  30  contacts the first leg  54  of the primary pawl  50  and applies a rotational force to the first leg  54  opposite the direction indicated by arrow B (see  FIG. 2 ). This rotational force causes the primary pawl  50  to rotate about pin  52  such that second leg  56  compresses the spring  22  thereby allowing the primary pawl  50  to rotate out of engagement with the claw  30 . The biasing force of the spring  22  causes the first leg  54  of the primary pawl  50  to rotate back into engagement with the claw  30  to contact the primary shoulder  36 . The aforementioned claw  30  and primary pawl  50  are provided as a non-limiting embodiment. It should be appreciated that numerous other configurations of the claw and pawl are considered to be within the scope of an exemplary embodiment of the invention. 
     An end piece  90  is fixed to the primary pawl  50  about pin  52  for uniform rotation with the primary pawl  50 . An inner lever  60  is pivotally mounted adjacent end piece  90  and the primary pawl  50  at pin  52  for rotation between a first position ( FIG. 1 ) and a second position ( FIG. 3 ). The inner lever  60  extends across the latch  20  adjacent hole  32  of the claw  30 . In one embodiment, the inner lever  60  is T-shaped such that the base of the T extends from the pin  52  towards the center of the claw  30  and the head  62  of the T is disposed across the claw  30  from hole  32  to a second shoulder  38  of claw  30 . The inner lever  60  additionally includes a tail  64  substantially perpendicular to the plane of the T-shaped body. The tail  64  extends adjacent a protrusion  92  from the surface of the end piece  90 . When the protrusion  92  abuts the tail  64  of the inner lever  60 , the tail  64  prevents further rotation of the end piece  90  and the primary pawl  50  in the direction of arrow B. 
     A secondary pawl  70  is disposed on a side of the claw  30  adjacent head  62  and opposite primary pawl  50 . The secondary pawl  70  includes a base pawl  72  and a connector  74  that extends in the direction of the second shoulder  38  of the claw  30  and the head  62  of the inner lever  60 . The connector  74  and base pawl  72  are fastened together at pin  76  such that the base pawl  72  and the connector  74  rotate as a single body between a first position and a second position. A biasing force, provided by a torsion spring (not shown) for example, rotates the secondary pawl  70  into a first position ( FIG. 1 ). An external rotational force may be applied to the secondary pawl  70 . In an exemplary embodiment, the secondary pawl  70  is mechanically connected to a vehicle handle  75 . A blocking lever  80  is pivotally mounted about its center to the latch  20  adjacent an end of the connector  74 , near the inner lever  60  and second shoulder  36  of claw  30 . The blocking lever  80  pivots between a first position ( FIG. 1 ) and a second position ( FIG. 3 ). A blocking member  82  extends from a portion of the blocking lever  80 . In the illustrated embodiment, the blocking member  82  is positioned at a corner of the blocking lever  80  closest to hole  32 . The blocking lever  80  is biased in the direction indicated by arrow C, such as by a torsion spring (not shown) for example, into a second position where the blocking member  82  is rotated toward the center of the claw  30 . 
     Referring now to  FIGS. 1 and 2 , when in a first position, the secondary pawl  70  is rotated in the direction indicated by arrow D around pin  76  towards the center of the latch  20 . In a first position, the inner lever  60  is at a position relative to the latch  20  such that a second end  62   b  of head  62  of the inner lever  60  contacts the base pawl  72  of the secondary pawl  70 . When the secondary pawl  70  is in a first position, the inner lever  60  is retained in a first position. When the secondary pawl  70  is in a first position, an end of the connector  74  is located adjacent the blocking lever  80  and applies a rotational force to the blocking lever  80  opposite its biasing force. This rotates the blocking lever  80  to a first position substantially parallel to the head  62  of the inner lever  60 . Also, when the inner lever  60  is in a first position, any potential rotation of the blocking lever  80  is limited by the inner lever  60 . Thus, when the secondary pawl  70  is in a first position, the inner lever  60  is also in a first position and the blocking lever  80  is in a first position. 
     Referring now to  FIG. 3 , when a force is applied to the secondary pawl  70 , such as by lifting a handle  75  connected to the secondary pawl  70  via a mechanical linkage (not shown), the secondary pawl  70  rotates about pin  76  in a direction opposite arrow D, away from the claw  30 . This rotation disengages the base pawl  72  from the second end  62   b  of the inner lever  60 , thereby allowing the inner lever  60  to rotate to a second position. In the second position, the inner lever  60  is rotated towards the bottom of claw  30  such that the first end  62   a  of the inner lever  60  is adjacent hole  32 . By rotating the secondary pawl  70  to the second position, the rotational force applied by the connector  74  to the blocking lever  80  is removed. The blocking lever  80  is biased into its second position wherein the blocking member  82  is adjacent hole  32  and the first end  62   a  of head  62 . When the blocking lever  80  is in this second position, the blocking member  82  contacts the first end  62   a  of the head  62  of inner lever  60  to retain the inner lever  60  in a second position and to prevent movement of the inner lever  60  while a force continues to be applied to the secondary pawl  70 . 
     Lifting a handle  75  connected to the latch  20  also signals an electric motor  57  to disengage the primary pawl  50  from the claw  30  to allow the claw  30  to rotate to a fully open position. The inner lever  60  rotates from a first position to a second position while the primary pawl  50  is disengaged from the claw  30 . By holding the inner lever  60  in a second position, the tail  64  of the inner lever  60  engages the protrusion  92  of the end piece  90  to prevent the primary pawl  50  from rotating back into engagement with the claw  30 . Consequently, as long as a handle  75  remains lifted and the inner lever  60  is retained in a second position, the primary pawl  50  will be unable to rotate into engagement with the claw  30 . 
     Once the handle  75  is released, the rotational force applied to the secondary pawl  70  is removed such that the secondary pawl  70  is biased back into a first position. The rotation of the secondary pawl  70  causes connector  74  to reapply a rotational force to the blocking lever  80  opposite its biasing force causing the blocking lever  80  to rotate to its first position. Rotation of the blocking lever  80  into a first position disengages the blocking member  82  from the first end  62   a  of the inner lever  60 , thereby allowing the inner lever  60  to freely rotate back to a first position. As a result, the unrestrained biasing force of spring  22  will rotate the primary pawl  50  back toward engagement with the claw  30 . Once in the first position, the base pawl  72  will again contact the second end  62   b  of head  62 , thereby limiting movement of the inner lever  60  from the first position until a connected handle  75  is lifted. 
     Embodiments of the invention provide advantages in retaining the latch in an open position while the vehicle handle coupled to the latch is lifted. The invention prevents movement of the latch until the vehicle handle has been released. In addition, the invention does not require significant additional components or space. 
     While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.