Abstract:
A vehicle latch assembly ( 10 ) includes a release member ( 40 ) pivotally mounted on a housing ( 20 ) for movement from a start position where a catch ( 24 ) secures a closure member striker ( 18 ) and a released position where a pawl ( 32 ) permits the catch to move to a released position. An actuating portion ( 42 ) of the release member holds the pawl ( 32 ) in a released position if the catch ( 24 ) after being released by the pawl does not move to its released position because the associated closure member remains closed. A positioning member ( 66 ) cyclically positions a drive portion ( 62 ) of an output gear ( 60 ) of a worm gear drive ( 54 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. provisional application Serial No. 60/314,192 filed Aug. 22, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to a vehicle closure member latch assembly and has particular utility for use with vehicle deck lids.  
           [0004]    2. Background Art  
           [0005]    Vehicle closure members conventionally include a latch assembly for selectively securing a striker to hold the closure member in a closed position with respect to an access opening of an associated vehicle body. For example, vehicle deck lids for which the latch assembly of the present invention has particular utility are conventionally counterbalanced to an open position by torque rods and are selectively held in the closed position by the cooperation of a latch assembly and an associated striker. Normally the striker is mounted on the vehicle body and the latch assembly is mounted on the vehicle deck lid; however, the reverse mounting is also sometimes used with the striker mounted on the vehicle deck lid and the latch assembly mounted on the vehicle body. Upon unlatching of the striker by the latch assembly, the counterbalancing provided by the torque rods moves the closure member to an open position with or without manual assistance. However, in some instances ice or snow that accumulates can prevent the opening movement of the closure member. When the unlatching of the latch assembly is provided by an electric motor drive release, this condition can result in continual electric motor driving of the drive release until the closure member is moved to its open position whereupon an associated catch of the latch assembly moves to an unlatched position in a manner that terminates the electric motor driving through the accompanying movement of the latch assembly components.  
           [0006]    Prior art patents noted during an investigation conducted in connection with the present invention includes U.S. Pat. Nos. 5,074,603 Brackmann; 5,137,311 Brackmann-Horst; 5,938,253 Szablweski et al.; 6,109,671 Roncin et al; 6,264,253 Takaishi; and 6,267,420 Miyagawa.  
         SUMMARY OF THE INVENTION  
         [0007]    An object of the present invention is to provide an improved vehicle closure member latch assembly.  
           [0008]    In carrying out the above object, the vehicle latch assembly of the invention is constructed to hold a closure member in a closed position with respect to a vehicle opening defined by a vehicle body member. The latch assembly is actuatable to permit movement of the closure member from the closed position to an open position so as to allow access through the vehicle opening. The construction of the latch assembly includes a housing mountable on one of the members. A catch of the latch assembly is pivotally mounted on the housing for movement between: a latched position for securing a striker mounted on the other member to hold the closure member in the closed position with respect to the vehicle body member, and an unlatched position that releases the striker and permits the closure member to move from the closed position to the open position. The catch has a pawl engagement portion. A pawl of the latch assembly is pivotally mounted on the housing for movement between: a blocking position where the pawl engages the catch to hold the catch in its latched position and thereby maintain the closure member in the closed position, and a released position where the pawl is disengaged from the catch to permit movement of the catch to the unlatched position and thereby permit movement of the closure member from the closed position to the open position. A release member of the latch assembly has an actuating portion and is pivotally mounted on the housing for actuatable movement from: a start position where the catch is held in the latched position by the pawl in its blocking position, to a released position where the actuating portion of the release member engages and moves the pawl to its released position to permit movement of the catch to its unlatched position. The pawl engagement portion of the catch engages the pawl as the catch moves from its latched position to its unlatched position as the striker is released from the catch concomitant with movement of the closure member from the closed position to the open position. The actuating portion of the release member engages the pawl to maintain the pawl in its release position when the catch does not move to its unlatched position because the closure member does not move from the closed position to the open position. An actuator of the latch assembly actuates movement of the release member from its start position to its released position to provide the pawl movement from its blocking position to its released position.  
           [0009]    The latch assembly includes a spring that biases the catch toward its unlatched position and that biases the pawl toward its blocking position. In addition, the latch assembly includes a spring that biases the release member toward its start position. A sensor of the latch assembly senses the location of the release member.  
           [0010]    The actuator of the latch assembly is disclosed as including an electric motor and worm gear drive that selectively moves the release member from its start position to its released position. The worm gear drive includes an output gear that is rotatively driven by the electric motor, and the output gear has a drive portion. The release member has a driven surface that is engaged by the drive portion of the output gear to move the release member from its start position to its released position.  
           [0011]    The actuator of the latch assembly is also disclosed as including a key nut that selectively moves the release member from its start position to its released position. The key nut includes an actuating portion, and the release member has an opening that receives the actuating portion of the key nut and has a cam surface that is moved by the actuating portion of the key nut to move the release member from its start position to its released position.  
           [0012]    The actuator of the latch assembly is further disclosed as including a remote cable release that is connected to the release member and is selectively actuatable to move the release member from its start position to its release position.  
           [0013]    The actuator is actually disclosed as including an electric motor and a worm gear drive together with a key nut that each selectively moves the release member from its start position to its release position as well as also including a remote cable release that is connected to the release member and selectively actuatable to move the release member from its start position to its release position.  
           [0014]    In addition to the actuator including an electric motor driven output gear having a drive portion that engages and moves the release member to move the release member from its start position to its released position, the latch assembly also includes a positioning member that is moved from a start position to a blocking position when the pawl is moved from its blocking position to its released position with respect to the catch regardless of whether or not the catch moves from its latched position to its unlatched position. The positioning member in its blocking position engages the drive portion of the output gear to position the output gear in a start position thereof in preparation for another cycle for actuating the release member for movement from its start position to its release position. A spring extends between a catch and the positioning member to bias the catch toward its unlatched position, to bias the positioning member toward its start position, and to bias the pawl toward its blocking position by engagement of the positioning member with the pawl. The positioning member has a first arm including a blocking portion that engages the drive portion of the output gear to position the output gear in its start position, and the positioning member has a second arm connected to the spring which is also connected to the catch. A sensor senses the location of the positioning member. Thus, there is a first sensor that senses the location of the release member and a second sensor that senses the location of the positioning member.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side elevational view of a vehicle having a latch assembly constructed in accordance with the invention to hold a closure member, such as the rear deck lid shown, in a closed position shown by a solid line representation and to selectively permit movement thereof to an open position shown by phantom line representation.  
         [0016]    [0016]FIG. 2 is a view of the latch assembly which is shown in a latched position holding a striker so as to maintain the closure member in its closed position.  
         [0017]    [0017]FIG. 3 is a view that illustrates the latch assembly after actuation thereof to commence unlatching of the latch assembly.  
         [0018]    [0018]FIG. 4 is a view that illustrates the latch assembly at a further stage of its unlatching after a striker has been released by a catch to permit opening movement of the closure member.  
         [0019]    [0019]FIG. 5 is a view illustrating the latch assembly after it has been actuated to permit the catch to move to its unlatched position but without any such movement because the closure member is prohibited from such movement such as by accumulated ice or snow.  
         [0020]    [0020]FIG. 6 is a view illustrating the manner in which the latch assembly is released by key nut operation.  
         [0021]    [0021]FIG. 7 is a view of another embodiment of the latch assembly which includes a remote cable release for providing the unlatching.  
         [0022]    [0022]FIG. 8 is a view that illustrates the remote cable release embodiment of the latch assembly after its catch has been unlatched.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    With reference to FIG. 1, a vehicle generally indicated by  10  is disclosed as including a closure member that is embodied by a rear deck lid  12  that is movable between a solid line indicated closed position and a phantom line indicated open position to permit access through a vehicle opening  14  into the associated vehicle trunk storage compartment. A latch assembly  16  constructed in accordance with the invention is illustrated as being mounted on the deck lid  12  and as cooperating with a vehicle body mounted striker  18  to hold the deck lid in its closed position and selectively permit movement thereof to its open position by actuation of the latch assembly  16  to release the striker  18  as is hereinafter more fully described. It should be appreciated that the latch assembly  16  is conventionally mounted on the closure member provided by the deck lid  12  and the striker  18  is mounted on a vehicle body member adjacent the rear of the vehicle storage compartment trunk, but the relative position can also be reversed so that the latch assembly is on the vehicle body and the striker is on the deck lid.  
         [0024]    With reference to FIG. 2, the latch assembly  16  includes a housing  20  having fastener openings  22  for receiving suitable fasteners such as threaded studs or bolts utilized to mount the latch assembly by threaded connections. A catch  24  of the latch assembly is pivotally mounted by a pin  26  on the housing  20  for movement between a latched position shown in FIG. 2 and a released position as shown in FIG. 4. The catch  22  has a throat  28  that receives the striker  18  in its latched position of FIG. 2 so as to secure the associated deck lid closure member in its closed position. In its released position shown in FIG. 4, the catch throat  28  releases the striker  18  to permit movement of the deck lid closure member to its open position in order to permit access through the vehicle opening. Subsequent closing of the closure member causes the striker to pivot the catch  24  back to its latched position for latching as is hereinafter more fully described. The catch  24  also has a pawl engagement portion  30  whose operation is subsequently described in connection with FIG. 4.  
         [0025]    As shown in FIG. 2, the latch assembly  16  also includes a pawl  32  pivotally mounted by a pin  34  on the housing  20  for movement between the blocking position illustrated and a released position as shown in FIG. 3. In the blocking position of FIG. 2, a blocking notch  36  of the pawl receives and engages a lobe  38  of the catch  24  to hold the catch in its latched position and thereby maintain the deck lid closure member in the closed position. In the release position of FIG. 3, the pawl  32  has its notch  36  disengaged from the catch  24  at its lobe  38  to permit movement of the catch to its unlatched position shown in FIG. 4 so that the striker  18  is released to permit movement of the deck lid closure member from the closed position to the open position.  
         [0026]    A release member  40  of the latch assembly has an actuating portion  42  and is pivotally mounted by a pin  44  on the housing  20  for actuable movement from a start position shown in FIG. 2 to a released position shown in FIG. 3. When the release member  40  is in its start position shown in FIG. 2, the catch  24  is held in the latched position by the pawl  32  in its blocking position as previously described. The actuating movement as is hereinafter more fully described moves the release member  40  to its released position of FIG. 3 where the actuating portion  42  of the release member engages and moves the pawl  32  to its released position to permit movement of the catch  24  to its unlatched position. Under normal circumstances, the catch  24  then pivots to its unlatched position of FIG. 4 as the striker  18  is released as shown in FIG. 4 and the pawl engagement portion  30  of the catch then pivots the pawl  32  clockwise and releases the actuating portion  42  of the release member  40  to permit release member movement back to its start position under a spring bias that is hereinafter described. However, when the closure member is not free to open such that the striker  18  does not move relative to the catch  24  as shown in FIG. 5 even though the pawl  32  has released the catch, a notched distal end  46  of the actuating portion  42  of release member  40  engages a lobe  48  of the pawl  32  to maintain the pawl in its released position such that the latch does not again latch and prevent opening of the closure member once the ice, snow or other accumulation etc. is removed to permit opening of the closure member.  
         [0027]    An actuator collectively indicated by  50  is actuatable to move the release member from its start position of FIG. 2 to its released position of FIG. 3 in order to provide the pawl member movement from its blocking position to its release position for unlatching of the latch assembly. This actuator is mounted on the housing  20  and includes an electric motor  52  and worm gear drive  54  that is driven by the electric motor to provide the movement of the release member. More specifically, the electric motor  52  has a rotary output  56  that rotatively drives a worm gear  58  of the worm gear drive  54  which also includes a rotary output gear  60 . This output gear  60  has a drive portion  62 , and the release member  40  has a driven surface  64  that is engaged by the drive portion of the output gear  60  upon rotary driving thereof provided by the electric motor so that the release member moves from its start position of FIG. 1 to its released position illustrated in FIG. 5.  
         [0028]    As illustrated in FIG. 2, the latch assembly  16  includes a positioning member  66  that is pivotally mounted on the housing  20  by the same pin  44  that pivotally mounts the release member  40 . More specifically, this positioning member  66  is mounted for movement from the start position shown in FIG. 2 to a blocking position illustrated in FIG. 4, this movement being provided by a pin  68  on the pawl when the pawl is moved from its blocking position to its released position with respect to the catch  24 . In the blocking position as illustrated in FIG. 4, the positioning member  66  engages the drive portion  62  of the output gear  60  of worm gear drive  54  to position the output gear in preparation for the next releasing actuation cycle.  
         [0029]    As shown in FIG. 2, the latch assembly includes a spring  70  having one end secured to a pin  72  on the catch  24  and having another end secured in an opening  74  of the positioning member  66 . This spring  70  biases the catch  24  to its released position of FIG. 4 and in addition biases the positioning member  66  to its start position of FIG. 2. Furthermore, engagement of the positioning member  66  with the pin  68  on the pawl also biases the pawl toward its blocking position shown in FIG. 2.  
         [0030]    Latch assembly  16  as shown in FIG. 2 includes another spring  76  that is wound around the pin  44  and has an arm  78  extending to the release member  40  and another arm  80  extending to a shaft  84  about which the output gear  60  rotates. This spring  76  biases the release member  40  to its start position of FIG. 2. Thus, the actuating movement of the release member  40  by the electric motor driven worm gear drive  54  is against the bias of the spring  76  which thus provides pressure between the drive portion  62  of the output gear  60  and the driven surface  64  of the release member  40 . Likewise, the spring  70  exerts a clockwise bias on the positioning member  66  which in turn biases the pin  68  on pawl  32  in a counterclockwise direction and in turn biases the actuating portion  42  of the release member  40  so as to also resist the actuating movement of the worm gear drive. Furthermore, it will be noted that after the output gear  60  has rotated sufficiently far to provide the latch release operation, its drive portion  62  passes over a lobe  86  of the driven surface  64  in preparation for moving back to its start position and to then also permit the release member to move back to its start position when permitted to do so by the unlatching of the latch. As previously mentioned, the positioning member  66  will then be moved to its blocking position of FIG. 5 so as to limit the rotation of the output gear  60  and position the drive portion  62  against further movement. Normally, the electric motor  62  will be electrically energized with a power duration sufficient to provide the rotary movement to the start position without maintaining the electrical supply to the motor so that it over heats after the rotation is blocked by the positioning member  66 .  
         [0031]    A sensor  88  senses the position of the release member  40  and functions to provide an alarm reset. Furthermore, a sensor  90  senses the position of the positioning member  66  to provide a closure member ajar signal.  
         [0032]    The latch actuator also includes a key nut  92  that is rotatively moved by a key operated lock cylinder that is not shown. This key nut  92  as shown in FIG. 2 includes an actuator portion  94 , and the release member  40  has an opening  96  that received the actuating portion  94  of the key nut. More specifically, the release member opening  96  has a cam surface  98  that is moved by the actuating portion  94  of the key nut  92  to move the release member from its start position shown in FIG. 5 to its released position shown in FIG. 6.  
         [0033]    As shown in FIGS. 7 and 8, the latch assembly  16  also includes a remote cable release  100  that has a cable  102  connected to an arm  104  of the release member  40  such that pulling of the cable rotates the release member counterclockwise about the pin  44  for movement from its start position of FIG. 7 to its release position of FIG. 8.  
         [0034]    Normally the latch assembly will have the electric motor driven worm gear drive release  54  to permit unlatching of the latch assembly by a vehicle occupant compartment actuation button, as well as having the key nut  92  for permitting exterior key release actuation of the latch assembly, and the remote cable release  100  will permit release of the latch assembly from within the trunk storage compartment as now required by certain governmental regulations.  
         [0035]    It will be noted in FIG. 2 that the construction of the positioning member  66  includes a first arm  106  having a blocking portion  108  which moves into the path of the output gear drive portion  62  as the release member  40  is moved to its FIG. 3 release position in order to provide the positioning the output gear as previously described. A second arm  110  extends from the pin  44  that pivotally mounts the positioning member  66  and includes the hole  44  that connected to the adjacent end of the spring  70  that provides the biasing of the catch  24  to its released position and the biasing of the positioning member  66  to its start position as well as the biasing of the pawl  32  to its blocking position through the engagement of the arm  110  with the pin  66 .  
         [0036]    While the preferred embodiments for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for carrying out the invention as described by the following claims.