Abstract:
A closure assembly and method of operation for a vehicle closure includes a latch for selectively securing the closure to the vehicle, and a lockable bumper assembly that includes an electronic locking mechanism that can selectively secure the bumper in a pocket of the base to add an additional mechanism for securing the closure to the vehicle. The locking mechanism may be controlled to secure the bumper to the base after a controller detects that the latch is latched and the bumper is seated in the pocket of the base.

Description:
BACKGROUND OF INVENTION 
     The present invention relates generally to closures used on automotive vehicles and more particularly to bumpers that are used on vehicle closures such as hoods and liftgates. 
     While operating a vehicle, the vehicle&#39;s liftgates may tend to move in their body openings, thus potentially creating undesirable noise and possibly damage to the vehicle. For example, liftgate chucking, which is a rattle condition that occurs during vehicle operation causing hard contact between a latch and striker, may sometimes occur. This situation is typically avoided by using wedge systems with the liftgate. Liftgate wedges are devices that provide additional constraint of the liftgate to improve the stability of the liftgate within the opening. The additional constraint tends to reduce unwanted noise, squeaks and rattles. However, these wedge systems are difficult to align and typically only provide marginal control over the movement of the liftgates in their openings. 
     In addition, for some vehicles, the corners of the hood may have a tendency to lift at high vehicle speeds due to aerodynamic loads. This condition is sometimes addressed by employing wedges, bumpers or additional latches. However, wedges and bumpers tend to only constrain the hood in one or two directions and are difficult to adjust, where too much contact causes high closing efforts and too little contact substantially reduces their effectiveness. 
     SUMMARY OF INVENTION 
     An embodiment contemplates a method for releasably securing a closure on a vehicle to a vehicle body, the method comprising the steps of: moving the closure from an open position to a closed position against the vehicle body; actuating a latch to retain the closure against the vehicle body upon the closure reaching the closed position; inserting a bumper, which is mounted on one of the closure and the vehicle body, into a pocket of a base, which is mounted on the other of the closure and the vehicle body, as the closure approaches the closed position; detecting if the latch is actuated to retain the closure against the vehicle body; detecting if the bumper is fully inserted into the pocket; and actuating an electronic locking mechanism to secure the bumper to the base after detecting that the latch is actuated to retain the closure against the vehicle body and after detecting that the bumper is fully inserted into the pocket. 
     An embodiment contemplates a method for releasably securing a closure on a vehicle to a vehicle body, the method comprising the steps of: receiving a signal to open the closure when closed; controlling an electronic locking mechanism to release a bumper, which is mounted on one of the closure and the vehicle body, from a pocket of a base, which is mounted on the other of the closure and the vehicle body, wherein the bumper, when in engagement with the base, restrains movement of the closure relative to the vehicle body in three axial directions; releasing a latch, which secures the closure in a closed position, to release the closure from the vehicle body, the latch being released after the electronic locking mechanism releases the bumper; and moving the closure from the closed position to an open position. 
     An embodiment contemplates a closure assembly that is releasably securable to a vehicle body of a vehicle having a controller. The closure assembly comprises a latch and a lockable bumper. The latch is secured to the closure and releasably engages the vehicle body, with the latch communicating with the controller to indicate a state of the latch being latched or unlatched. The lockable bumper assembly includes a bumper mounted to one of the closure and the vehicle body and a base mounted to the other of the closure and the vehicle body. The base includes a pocket complimentary in shape to the bumper for receiving a portion of the bumper therein, a bumper closed sensor assembly that detects when the bumper is seated in the pocket and communicate this status to the controller, and at least one electronic locking mechanism including a movable retaining flange, with the actuation of the electronic locking mechanism controllable by the controller. The bumper includes a retaining surface that is engageable with the movable retaining flange to selectively secure the bumper in the pocket. 
     An advantage of an embodiment is that the lockable bumper assembly provides an anti-chucking device for liftgates and a device for resisting hood liftoff at high speeds, while avoiding the difficulties with the alignment of wedges and avoiding the need for additional latches. The lockable bumper assembly provides for three-way constraint, thus significantly reducing movement of the closure relative to the vehicle body while the vehicle is operating. This is accomplished without the need to increase closing efforts for the vehicle closures. 
     In addition, an advantage of an embodiment is that the lockable bumper assembly provides an additional theft deterrent by preventing the hood or liftgate from being opened when an electronic locking mechanism in the lockable bumper assembly is engaged. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic plan view of a vehicle. 
         FIG. 2  is a schematic section view of a lockable bumper mounted to vehicle structure in an open position according to a first embodiment. 
         FIG. 3  is a schematic section view similar to  FIG. 2 , but showing the lockable bumper in a closed position. 
         FIG. 4  is a schematic section view of a lockable bumper in an open position according to a second embodiment. 
         FIG. 5  is a schematic section view similar to  FIG. 4 , but showing the lockable bumper in a closed position. 
         FIG. 6  is a schematic section view of a lockable bumper in an open position according to a third embodiment. 
         FIG. 7  is a schematic section view similar to  FIG. 6 , but showing the lockable bumper in a closed position. 
         FIG. 8  is a schematic section view of a lockable bumper in an open position according to a fourth embodiment. 
         FIG. 9  is a schematic section view similar to  FIG. 8 , but showing the lockable bumper in a closed position. 
         FIG. 10  is a schematic section view of a lockable bumper in an open position according to a fifth embodiment. 
         FIG. 11  is a schematic section view similar to  FIG. 10 , but showing the lockable bumper in a closed position. 
         FIG. 12  is a schematic section view of a lockable bumper in an open position according to a sixth embodiment. 
         FIG. 13  is a schematic section view similar to  FIG. 12 , but showing the lockable bumper in a partially closed position. 
         FIG. 14  is a schematic section view similar to  FIG. 12 , but showing the lockable bumper in a closed position. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a vehicle  20  having closures, such as a hood  22  and a liftgate  24 , each interacting with a pair of lockable bumper assemblies  26 . While a hood  22  and a liftgate  24  are discussed herein, the lockable bumper assemblies  26  may be applied to other vehicle closures as well. Also, there may be only one lockable bumper assembly  26  associated with a particular closure rather than multiple ones, if so desired. 
     The hood  22  is secured to a front portion of the vehicle body  28  via a hood latch  30 , and the liftgate  24  is secured to rear portion of the vehicle body  28  via a liftgate latch  32 . A first pair of lockable bumper assemblies  26  mount between the body  28  and the hood  22 , while a second pair of lockable bumper assemblies  26  mount between the body  28  and the liftgate  24 . The lockable bumper assemblies  26  are not meant to take the place of the latches  30 ,  32 , but are in addition to the latches  30 ,  32 . 
     A controller  34 , which may be a body control module, is located in the vehicle  20  and is in communication with the lockable bumper assemblies  26 , the hood latch  30  and the liftgate latch  32 . The controller  34  may also be in communication with a liftgate release or liftgate open button  36 , a liftgate handle  38 , a hood release lever  40  and/or a key fob  42  having buttons relating to release or closure of the liftgate  24  or possibly the hood  22 . The controller  34  may be made up of different combinations of electronics hardware and software as is known to those skilled in the art and may be a single controller or multiple separate controllers in communication with one another. 
       FIGS. 2 and 3  illustrate a first embodiment of the lockable bumper assembly  26  that may be employed with the vehicle of  FIG. 1 . The bumper assembly  26  includes a bumper  46 , which includes a retaining surface  48  (in this embodiment, a slot) and a mounting member  50 , such as, for example, a threaded stud. The mounting member  50  may be mounted to the closure structure  52 , which may be part of a hood, liftgate or other vehicle closure structure. The bumper  46  may be a truncated cone shape. 
     The bumper assembly  26  also includes a base  54  that is mounted to the vehicle body  28 . Alternatively, the base  54  may be mounted to the closure structure  52 , with the bumper  46  mounted to the vehicle body  28 . The base includes a pocket  56  that is complimentary in shape to the bumper  46  and allows the bumper  46  to be received and nest therein. 
     The base  54  also includes a bumper-closed sensor assembly  58  that is configured to detect when the bumper  46  is seated in the pocket  56 . This sensor assembly  58  may include a channel  60  through which a plunger  62  can telescopically slide. A plunger spring  64  may be mounted in the channel  60  and bias the plunger  62  into the pocket  56 . The plunger  62 , channel  60  and plunger spring  64  cooperate to retain the plunger  62  in the channel  60 . A bumper engagement switch  66  may be mounted in the channel  60 , opposite the pocket  56 , and positioned to be actuated when the plunger  62  is pushed into the channel  60  by the bumper  46 . 
     The base  54  also includes at least one electronic locking mechanism  68  that includes an electronically actuatable, moving mechanism  70  that controls the movement of a movable retaining flange  72 . The moving mechanism  70  can move the retaining flange  72  into and out of contact with the retaining surface  48  on the bumper  46  when the bumper  46  is received in the pocket  56 . The moving mechanism  70  is preferably configured so that the retaining flange  72  extends into the pocket  56  when no electric current is applied to the electronic locking mechanism  68  and is retracted from the pocket when an electric current is applied to the electronic locking mechanism  68 . The bumper engagement switch  66  and the electronic locking mechanism  68  may be in communication with the controller  34  (shown in  FIG. 1 ). 
     The moving mechanism  70  may be made of, for example, a shape memory alloy that changes shape as heat is applied, resulting in motion, and that returns to the original shape after the heat is removed. The heat applied may be from an electric current that is activated and deactivated by the controller  34 . Alternatively, other types of electronically actuatable, moving mechanisms may be employed instead, if so desired. 
     The operation of the lockable bumper assembly  26  will be described with reference to  FIGS. 1-3 . When the closure (such as a hood  22  or liftgate  24 ) is partially or fully open, the bumper  46  is located outside of the pocket  56  (see position in  FIG. 2 ). Thus, the bumper  46  does not push down on the plunger  62 , resulting in the bumper engagement switch  66  indicating an open position. While the bumper engagement switch  66  indicates an open position, the controller  34  assures that power is provided to the electronic locking mechanisms  68 , thus keeping the movable retaining flanges  72  in retracted positions. 
     As the closure structure (such as a hood  22  or liftgate  24 ) is moved to the closed position, the bumper  46  moves into the pocket  56 . The movement of the closure may be manual or may be an automated closing process that is activated by the key fob  42  or a button on the vehicle  20 . The truncated conical shape of the bumper  46  allows for a small amount of misalignment of the bumper  46  relative to the pocket  56 , with the sides of the pocket  56  guiding the bumper  46 . As the closure structure reaches the fully closed position (see position in  FIG. 3 ), the bumper  46  pushes the plunger  62  against the bias of the plunger spring  64  and into contact with the bumper engagement switch  66 , which signals the controller  34  that the bumper  46  is seated in the base  54 . At this point, with the closure in a fully closed position, the latch (a hood latch  30  or a liftgate latch  32 , as the case may be) will be engaged, with the controller  34  receiving a signal that the latch is engaged. 
     With the latch engaged, a signal is sent from the controller  34  to the electronic locking mechanism  68 , causing the power to the locking mechanism  68  to be shut off. This causes the moving mechanism  70  to push the movable retaining flanges  72  into engagement with the retaining surface  48  of the bumper  46 . The bumper  46  is now secured to the base  54  in the fore-aft, cross-vehicle and vertical directions. The bumpers  46 , then, act as anti-chucking devices and a theft deterrent. 
     Alternatively, when the controller  34  receives a signal that the latch is engaged, the controller may wait until the vehicle speed reaches about five kilometers per hour, for example, and then send a signal that causes the moving mechanism  70  to push the movable retaining flanges  72  into engagement with the retaining surface  48  of the bumper  46 . 
     For opening of a closed hood  22  or liftgate  24 , upon a vehicle operator actuating the liftgate handle  38 , using a key fob  42  to signal the vehicle  20  to open the liftgate, actuating a liftgate release button  36  or actuating a hood release lever  40 , the controller  34  will cause the electronic locking mechanisms  68  to retract the movable retaining flanges  72 . This allows the hood  22  or liftgate  24 , as the case may be, to open once the particular latch  30  or  32  has been released. 
       FIGS. 4 and 5  illustrate a second embodiment of the lockable bumper assembly  126  that may be employed with the vehicle of  FIG. 1 . The arrangement in  FIGS. 4 and 5  have many items in common with that of  FIGS. 2 and 3  and to avoid unnecessary repetition of the description, the same reference numbers have been used but falling within the 100-series. The significant difference between this embodiment and the first embodiment is the way that the electronic locking mechanisms  168  engage the bumper  146 . The electronically actuatable, moving mechanisms  170  engage movable retaining flanges  172  that are wedge-shaped and engage with a retaining surface  148  on the back side of the bumper  146 . 
     The lockable bumper assembly  126  essentially works the same as in the first embodiment. The bumper  146  pushes the plunger  162  against the bias of the plunger spring  164  into contact with the bumper engagement switch  166  as the bumper  146  becomes fully seated in the pocket  156  of the base  154 . When appropriate, the controller causes the moving mechanism  170  of the electronic locking mechanism  168  to push the retaining flanges  172  into engagement with the retaining surface  148 , locking the bumper  146  in place. 
       FIGS. 6 and 7  illustrate a third embodiment of the lockable bumper assembly  226  that may be employed with the vehicle of  FIG. 1 . The arrangement in  FIGS. 6 and 7  have many items in common with that of  FIGS. 2 and 3  and to avoid unnecessary repetition of the description, the same reference numbers have been used but falling within the 200-series. The significant difference between this embodiment and the first embodiment is the way that the electronic locking mechanisms  268  engage the bumper  246 , and the shape of the bumper  246 . The electronically actuatable, moving mechanisms  270  engage pivotable retaining flanges  272  via small plungers  282 . The retaining flanges  272  are wedge-shaped at one end and engage with a retaining surface  248  on a cross member  280  of an I-shaped bumper  246  when pivoted into the pocket  256 . The I-shaped bumper  246  is shaped to slide into the pocket  256  of the base  254  without contacting the retaining flanges  272  while they are recessed into cavities  281  in the base  254 . 
     The lockable bumper assembly  226  essentially works the same as in the first embodiment. The bumper  246  pushes the plunger  262  against the bias of the plunger spring  264  into contact with the bumper engagement switch  266  as the bumper  246  becomes fully seated in the pocket  256  of the base  254 . When appropriate, the controller causes the moving mechanism  270  of the electronic locking mechanism  268  to push on the retaining flanges  272 , thus pivoting them into engagement with the retaining surface  248  and locking the bumper  246  in place. 
       FIGS. 8 and 9  illustrate a fourth embodiment of the lockable bumper assembly  326  that may be employed with the vehicle of  FIG. 1 . The arrangement in  FIGS. 8 and 9  have many items in common with that of  FIGS. 2 and 3  and to avoid unnecessary repetition of the description, the same reference numbers have been used but falling within the 300-series. The significant difference between this embodiment and the first embodiment is the way that the electronic locking mechanisms  368  engage the bumper  346 , and the shape of the bumper  346 . The electronically actuatable, moving mechanisms  370  engage movable retaining flanges  372 , which are telescopically slidable along the path of guides  384 . The retaining flanges  372  have mushroom-shaped cross sections and engage with a retaining surface  348  on a concave curved portion  385  of a bumper  346 , having a somewhat I-shaped cross section, when slid into the pocket  356 . The bumper  346  is shaped to slide into the pocket  356  of the base  354  without contacting the retaining flanges  372 , which are recessed into cavities  386  in the base  354 . 
     The lockable bumper assembly  326  essentially works the same as in the first embodiment. The bumper  346  pushes the plunger  362  against the bias of the plunger spring  364  into contact with the bumper engagement switch  366  as the bumper  346  becomes fully seated in the pocket  356  of the base  354 . When appropriate, the controller causes the moving mechanism  370  of the electronic locking mechanism  368  to push on the retaining flanges  372 , thus sliding them into engagement with the retaining surface  348  and locking the bumper  346  in place. 
       FIGS. 10 and 11  illustrate a fifth embodiment of the lockable bumper assembly  426  that may be employed with the vehicle of  FIG. 1 . The arrangement in  FIGS. 10 and 11  have many items in common with that of  FIGS. 2 and 3  and to avoid unnecessary repetition of the description, the same reference numbers have been used but falling within the 400-series. The significant difference between this embodiment and the first embodiment is the way that the electronic locking mechanisms  468  engage the bumper  446 , and the shape of the bumper  446 . The electronically actuatable, moving mechanisms  470  engage movable retaining flanges  472 , which are telescopically slidable in cavities  488 . The retaining flanges  472  have a truncated triangle-shaped cross section and engage with a retaining surface  448  on a complimentary concave portion  489  of a bumper  446 , having a somewhat I-shaped cross section, when slid into the pocket  456 . The bumper  446  is shaped to slide into the pocket  456  of the base  454  without contacting the retaining flanges  472 , which are recessed into cavities  488  in the base  454 . 
     The lockable bumper assembly  426  essentially works the same as in the first embodiment. The bumper  446  pushes the plunger  462  against the bias of the plunger spring  464  into contact with the bumper engagement switch  466  as the bumper  446  becomes fully seated in the pocket  456  of the base  454 . When appropriate, the controller causes the moving mechanism  470  of the electronic locking mechanism  468  to push on the retaining flanges  472 , thus sliding them into engagement with the retaining surface  448  and locking the bumper  446  in place. 
       FIGS. 12-14  illustrate a sixth embodiment of the lockable bumper assembly  526  that may be employed with the vehicle of  FIG. 1 . The arrangement in  FIGS. 12-14  have many items in common with that of  FIGS. 8 and 9  and to avoid unnecessary repetition of the description, the same reference numbers have been used but falling within the 500-series. Similar to  FIGS. 8 and 9 , the movable retaining flanges  572  have mushroom-shaped cross sections and include guides  592  for allowing telescopic movement of the flanges  572 . Also, the retaining surfaces  548  of the bumper  546  are concave curved portions. In this embodiment, however, the flanges  572  are biased partially into the pocket  556  by support springs  593 . In addition, the electronically actuatable, moving mechanisms  570  are oriented ninety degrees to the direction of orientation in  FIGS. 8 and 9 . When actuated, the moving mechanisms  570  slide locks  594  behind the retaining flanges  572 , preventing them from disengaging with the bumper  546 . The other difference with the previous embodiments is that the bumpers  546  must push the retaining flanges  572  out of the way against the bias of the support springs  593  as they slide into and out of the pockets  556 . 
     While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.