Abstract:
A seat assembly includes a seat back operatively coupled to a seat cushion and a head restraint operatively coupled to the seat back. A bell-crank is pivotally coupled to the seat back and operatively coupled to the seat cushion and a head restraint latch mechanism. Initial pivotal movement of the seat back from a seating position toward a folded position pivots the bell-crank from a first position actuating the latch mechanism to disengage with the head restraint. Continued pivotal movement of the seat back to the folded position pivots the bell-crank to a second position operably disconnecting the bell-crank and seat cushion. Pivotal movement of the seat back from the folded position to the seating position pivots the bell-crank from the second position to the first position actuating the latch mechanism to a position for engagement with the head restraint upon return of the head restraint to a use position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a head restraint release cable for automotive seating. More specifically, the present invention relates to a head restraint release cable that is actuated in response to pivoting a seat back forwardly and once the release cable is actuated continued pivoting of the seat back does not continue to actuate the cable. 
         [0003]    2. Description of Related Art 
         [0004]    Many automotive seats include a head restraint that is operatively coupled to an upper end of a seat back. It is common that such head restraints are movable between an upright use position when the seat back is in a seating position and a tilted stowed position when the seat back is in a forwardly folded position. In some instances the head restraint is moved manually from the use position to the stowed position. In other instances, a release mechanism having a cable is provided to automatically move the head restraint from the use position to the stowed position. 
         [0005]    These cable-type release mechanisms are typically operatively coupled between a latch mechanism that locks the head restraint in the use position and a seat cushion such that when the latch mechanism is unlocked in response to pivoting the seat back from the seating position to the forwardly folded position the head restraint will pivot from the use position to the stowed position. One disadvantage of some cable-type release mechanisms is that once the latch mechanism is unlocked and the seat back continues to pivot to the forwardly folded position, a force continues to be applied to the cable. In order to prevent the cable from breaking and to prevent damage to the latch mechanism a compensation spring system is provided to allow additional stretching of the cable. These spring systems require excess cable length and result in increased costs due to additional parts and assembly labor. Additionally, these spring systems may result in unwanted operational noise due to spring stretching. 
         [0006]    Another disadvantage of some cable-type release mechanisms is that once the head restraint pivots from the use position to the stowed position the latch mechanism is re-set. Re-setting the latch mechanism when the seat back is in the forwardly folded position allows the head restraint to be returned to the use position prior to returning the seat back to the seating position. 
         [0007]    It is therefore desirable to provide a head restraint release cable having a disconnect such that once a head restraint is released from a use position by pivoting a seat back, continued pivoting of the seat back does not apply a force to the cable. It is further desirable to provide a head restraint release cable having a lockout such that a head restraint cannot be returned to a use position until a seat back is returned to a seating position. 
       SUMMARY OF THE INVENTION 
       [0008]    According to one embodiment of the present invention, a seat assembly includes a seat back operatively coupled to a seat cushion for pivotal movement between a seating position and a forwardly folded position. A head restraint is operatively coupled to the seat back for movement between a use position and a stowed position. The head restraint is biased to the stowed position. A latch mechanism is releasably coupled to the head restraint. A bell-crank is pivotally coupled to the seat back and is operatively coupled to the seat cushion and the latch mechanism. The bell-crank is operable between a first position with the seat back in the seating position and a second position with the seat back in the folded position. Initial pivotal movement of the seat back from the seating position toward the folded position pivots the bell-crank from the first position and actuated the latch mechanism to disengage with the head restraint. Continued pivotal movement of the seat back to the folded position pivots the bell-crank to the second position operably disconnecting the bell-crank and the seat cushion. Pivotal movement of the seat back from the folded position to the seating position pivots the bell-crank from the second position to the first position and actuates the latch mechanism to a position for engagement with the head restraint upon return of the head restraint to the use position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
           [0010]      FIG. 1  is a perspective view of a seat assembly with a seat back in an upright seating position and a head restraint in a use position; 
           [0011]      FIG. 2  is a perspective view of the seat assembly with the seat back in a forwardly folded position and the head restraint in a stowed position; 
           [0012]      FIG. 3  is a side view of a release mechanism according to a first embodiment of the invention with the seat back in the upright seating position; 
           [0013]      FIG. 4  is a side view of the release mechanism of  FIG. 3  with the seat back in the forwardly folded position; 
           [0014]      FIG. 5  is a side view of a release mechanism according to a second embodiment of the invention with the seat back in the upright seating position; and 
           [0015]      FIG. 6  is a side view of the release mechanism of  FIG. 5  with the seat back in the forwardly folded position. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0016]    Referring to the Figures, a seat assembly for use in an automotive vehicle is generally shown at  10 . The seat assembly  10  includes a seat cushion  12  and a seat back  14  for supporting an occupant thereon. The seat back  14  is operatively coupled to the seat cushion  12  by a pair of synchronized disc recliner mechanisms  16  to allow pivotal adjustment of the seat back  14  between an upright seating position, shown in  FIG. 1 , and a forwardly folded position, shown in  FIG. 2 . The seat assembly  10  also includes a head restraint  18  pivotally coupled to an upper end of the seat back  14 . The head restraint  18  pivots between an upright use position, shown in  FIG. 1 , and a forwardly tilted stowed position, shown in  FIG. 2 . The head restraint  18  is biased toward the stowed position. 
         [0017]    Referring to  FIGS. 3 and 4 , the construction of the seat cushion  12  includes a rigid seat cushion frame  20  for supporting a contoured foam pad encased by a trim cover as is conventional in the art. Similarly, the construction of the seat back  14  includes a rigid seat back frame  22  for supporting a contoured foam pad encased by a trim cover as is conventional in the art. An A-bracket  24  is integrally formed with or fixedly secured to the seat back frame  22  and a B-bracket  26  is integrally formed with or fixedly secured to the seat cushion frame  20 . In the embodiment shown, the A-bracket  24  is disposed laterally inward of the B-bracket  26  and the disc recliner mechanism  16  is operatively coupled between an outboard side  28  of the A-bracket  24  and an inboard side (not shown) of the B-bracket  26 . The disc recliner mechanism  16  defines a pivot axis  30  and the seat back  14  pivots about the pivot axis  30  relative to the seat cushion  12 . It is appreciated that as an alternative the A-bracket  24  may be disposed laterally outward of the B-bracket  26  such that the disc recliner mechanism  16  is operatively coupled between an inboard side (not shown) of the A-bracket  24  and an outboard side  32  of the B-bracket  26 , without varying from the scope of the invention. 
         [0018]    A release mechanism, generally shown at  34 , is operatively coupled to a latch mechanism  36  with a Bowden-type cable  38 . The release mechanism  34  unlocks the latch mechanism  36  in response to pivoting the seat back  14  from the upright seating position to the forwardly folded position, which allows the head restraint  18  to pivot from the use position to the stowed position. Referring to the latch mechanism  36 , a hook (not shown) is pivotally coupled to the upper end of the seat back  14  and pivots between a locking position and an unlocking position. In the locking position, the hook will engage with the head restraint  18  to maintain the head restraint  18  in the use position. In the unlocking position, the hook will not engage with the head restraint  18  even if the head restraint  18  is pivoted to the use position. The hook is biased to the locking position. 
         [0019]    Referring to the release mechanism  34 , a bell-crank  40  is rotatably coupled to the outboard side  28  of the A-bracket  24  at a bell-crank pivot  42  and an upper edge of the B-bracket  26  includes a tab or trigger finger  44  protruding therefrom. The bell-crank  40  and the trigger finger  44  are disposed in the same plane and the bell-crank  40  directly engages the trigger finger  44  during pivotal movement of the seat back  14 . The bell-crank  40  includes first and second arms  46 ,  48  that are generally perpendicular such that the first and second arms  46 ,  48  form approximately a ninety (90) degree angle therebetween. The bell-crank  40  is partially peripherally surrounded by a housing  50  that is integrally formed with or fixedly secured to the outboard side  28  of the A-bracket  24 . The housing  50  includes a front wall  52 , a top wall  54 , a rear wall  56  and a bottom wall  58  that defines an opening  60  through which a portion of the bell-crank  40  protrudes to engage the trigger finger  44 . A forward stop  62  is fixedly secured to an inner side of the front wall  52  and a rearward stop  64  is fixedly secured to an inner side of the top wall  54 . When the seat back  14  is in the upright seating position, the bell-crank  40  is oriented in a first position with the first arm  46  extending downwardly through the opening  60  in the housing  50  toward the B-bracket  26  and the second arm  48  abutting the forward stop  62 . With the bell-crank  40  in the first position, the first arm  46  is disposed generally rearward of the trigger finger  44 . When the seat back  14  is in the forwardly folded position, the bell-crank  40  is oriented in a second position with the second arm  48  extending downwardly through the opening  60  in the housing  50  toward the B-bracket  26  and the first arm  46  abutting the rearward stop  64 . With the bell-crank  40  in the second position, the second arm  48  is disposed generally forward of the trigger finger  44 . 
         [0020]    The Bowden-type cable  38  includes a cable sheath  66  and a cable  68  extending through the cable sheath  66 . The cable sheath  66  extends between and is coupled to or directly engages an outer side of the front wall  52  of the housing  50  and a bracket (not shown) adjacent the hook of the latch mechanism  36 . One end of the cable  68  passes through the bracket and is connected to the hook and another end of the cable  68  passes through an aperture (not shown) in the front wall  52  of the housing  50  and is connected to the second arm  48  of the bell-crank  40 . Rotating the bell-crank  40  in a counterclockwise direction from the first position to the second position pulls the cable  68 , which pivots the hook from the locking position to the unlocking position. In contrast, rotating the bell-crank  40  in the clockwise direction from the second position to the first position releases the cable  68  allowing the hook to return to the locking position. 
         [0021]    An extension spring  70  extends between the housing  50  and the bell-crank  40  to bias the bell-crank  40  in either the clockwise direction or the counterclockwise direction. More specifically, one end of the spring  70  is connected to the top wall  54  of the housing  50  and another end of the spring  70  is connected to the bell-crank  40  generally between the first and second arms  46 ,  48 . When the seat back  14  is in the upright seating position, the bell-crank  40  is in the first position and the spring  70  is oriented relative to the bell-crank pivot  42  such that the spring  70  biases the bell-crank  40  in the clockwise direction and maintains the second arm  48  abutting the forward stop  62 . When the seat back  14  is in the forwardly folded position, the bell-crank  40  is in the second position and the spring  70  is oriented relative to the bell-crank pivot  42  such that the spring  70  biases the bell-crank  40  in the counterclockwise direction and maintains the first arm  46  abutting the rearward stop  64 . 
         [0022]    In operation, beginning with the seat back  14  in the upright seating position, the bell-crank  40  is in the first position and the hook is in the locking position to maintain the head restraint  18  in the use position. The disc recliner mechanism  16  is actuated to allow the seat back  14  to pivot about the pivot axis  30  to the forwardly folded position. As the seat back  14  pivots forwardly, the first arm  46  of the bell-crank  40  engages the trigger finger  44 , which causes the bell-crank  40  to rotate in the counterclockwise direction. Rotating the bell-crank  40  in the counterclockwise direction pulls the cable  68 , which pivots the hook from the locking position to the unlocking position. With the hook in the unlocking position, the head restraint  18  automatically pivots to the stowed position. As the seat back  14  continues to pivot forwardly, the first arm  46  falls off or disengages with the trigger finger  44  and at the same time the spring  70  goes over-center of the bell-crank pivot  42 , which causes the bell-crank  40  to continue to rotate in the counterclockwise direction until the bell-crank  40  is in the second position with the first arm  46  abutting the rearward stop  64 . With the bell-crank  40  in the second position, the cable  68  is at a maximum pulled state such that continued pivoting of the seat back  14  toward the forwardly folded position does not continue to pull the cable  68 . Additionally, since the spring  70  is over-center the bell-crank  40  will remain in the second position until the spring  70  goes back over-center, and this in turn maintains the hook in the unlocking position. Thus, the bell-crank  40  acts as a lock-out feature because the head restraint  18  cannot be returned to the use position until the hook is returned to the locking position and the hook cannot be returned to the locking position until the bell-crank  40  returns to the first position. 
         [0023]    To return the head restraint  18  to the use position, the seat back  14  is pushed rearwardly to pivot the seat back  14  about the pivot axis  30  to the upright seating position. As the seat back  14  pivots rearwardly, the second arm  48  of the bell-crank  40  engages the trigger finger  44 , which causes the bell-crank  40  to rotate in the clockwise direction. Rotating the bell-crank  40  in the clockwise direction releases the cable  68 . As the seat back  14  continues to pivot rearwardly, the second arm  48  falls off or disengages with the trigger finger  44  and at the same time the spring  70  goes back over-center of the bell-crank pivot  42 , which causes the bell-crank  40  to continue to rotate in the clockwise direction until the bell-crank  40  is in the first position with the second arm  48  abutting the forward stop  62 . With the bell-crank  40  in the first position, the cable  68  is fully released, which allows the hook to pivot from the unlocking position to the locking position. With the hook in the locking position, the head restraint  18  can be manually returned to the use position. 
         [0024]    Referring to  FIGS. 5 and 6 , wherein like primed reference numerals represent similar elements as those disclosed above, in a second embodiment of the invention a release mechanism  34 ′ includes a cable pulling lever  72  and a link  74  operatively coupling a bell-crank  40 ′ and a Bowden-type cable  38 ′. The cable pulling lever  72  extends between a first proximal end  76  that is pivotally coupled to an outboard side  28 ′ of an A-bracket  24 ′ at a lever pivot  78  and a second distal end  80 . One end of the link  74  is pivotally coupled to the cable pulling lever  72  between the lever pivot  78  and the distal end  80  thereof and another end of the link  74  is pivotally coupled to the bell-crank  40 ′ generally between first and second arms  46 ′,  48 ′. A housing  50 ′ is configured to peripherally surround the cable pulling lever  72  and the link  74  and to partially peripherally surround the bell-crank  40 ′. Upper and lower stops  82 ,  84  are disposed within the confines of the housing  50 ′ and are fixedly secured to the outboard side  28 ′ of the A-bracket  24 ′. The upper stop  82  is disposed adjacent a top wall  54 ′ of the housing  50 ′ and the lower stop  84  is disposed adjacent a bottom wall  58 ′ of the housing  50 ′. When a seat back  14 ′ is in an upright seating position, the bell-crank  40 ′ is oriented in a first position with the first arm  46 ′ extending downwardly through an opening  60 ′ in the bottom wall  58 ′ of the housing  50 ′ toward a B-bracket  26 ′. With the bell-crank  40 ′ in the first position, the first arm  46 ′ is disposed generally rearward of a trigger finger  44 ′ protruding from an upper edge of the B-bracket  26 ′. In addition, with the bell-crank  40 ′ in the first position, the cable pulling lever  72  is oriented with the distal end  80  abutting the upper stop  82 . When the seat back  14 ′ is in a forwardly folded position, the bell-crank  40 ′ is oriented in a second position with the second arm  48 ′ extending downwardly through the opening  60 ′ in the bottom wall  58 ′ of the housing  50 ′ toward the B-bracket  26 ′ and the first arm  46 ′ abutting the lower stop  84 . With the bell-crank  40 ′ in the second position, the second arm  48 ′ is disposed generally forward of the trigger finger  44 ′. In addition, with the bell-crank  40 ′ in the second position, the cable pulling lever  72  is oriented with the distal end  80  spaced apart from the upper stop  82 . 
         [0025]    A cable sheath  66 ′ of the Bowden-type cable  38 ′ extends between and is coupled to or directly engages an outer side of the top wall  54 ′ of the housing  50 ′ and a bracket (not shown) adjacent a hook of a latch mechanism  36 ′. One end of a cable  68 ′ extending through the sheath  66 ′ passes through the bracket and is connected to the hook and another end of the cable  68 ′ passes through an aperture (not shown) in the top wall  54 ′ and is connected to the distal end  80  of the cable pulling lever  72 . Rotating the bell-crank  40 ′ in a counterclockwise direction from the first position to the second position pulls the link  74  downwardly to pivot the cable pulling lever  72  about the lever pivot  78  in a clockwise direction, thereby pulling the cable  68 ′ which pivots the hook from a locking position to an unlocking position. In contrast, rotating the bell-crank  40 ′ in the clockwise direction from the second position to the first position pushes the link  74  upwardly to allow the cable pulling lever  72  to pivot about the lever pivot  78  in the counterclockwise direction, thereby releasing the cable  68 ′ which allows the hook to return to the locking position. It is appreciated that connecting the cable  68 ′ to the cable pulling lever  72  allows for a greater amount of cable pull than rotation of the bell-crank  40  with the cable  68  directly connected thereto, as disclosed in the first embodiment. 
         [0026]    A torsion spring  86  is disposed about the lever pivot  78  of the cable pulling lever  72  to bias the cable pulling lever  72  in the counterclockwise direction. In turn, the cable pulling lever  72 , through the link  74 , biases the bell-crank  40 ′ in either the clockwise direction or the counterclockwise direction. When the seat back  14 ′ is in the upright seating position, the bell-crank  40 ′ is in the first position and the link  74  is oriented relative to a bell-crank pivot  42 ′ such that the torsion spring  86  acting through the cable pulling lever  72  and the link  74  biases the bell-crank  40 ′ in the clockwise direction and maintains the distal end  80  of the cable pulling lever  72  abutting the upper stop  82 . When the seat back  14 ′ is in the forwardly folded position, the bell-crank  40 ′ is in the second position and the link  74  is oriented relative to the bell-crank pivot  42 ′ such that the torsion spring  86  acting through the cable pulling lever  72  and the link  74  biases the bell-crank  40 ′ in the counterclockwise direction and maintains the first arm  46 ′ abutting the lower stop  84 . 
         [0027]    In operation, beginning with the seat back  14 ′ in the upright seating position, the bell-crank  40 ′ is in the first position and the hook is in the locking position to maintain a head restraint  18 ′ in a use position. A disc recliner mechanism  16 ′ is actuated to allow the seat back  14 ′ to pivot about the pivot axis  30 ′ to the forwardly folded position. As the seat back  14 ′ pivots forwardly, the first arm  46 ′ of the bell-crank  40 ′ engages the trigger finger  44 ′, which causes the bell-crank  40 ′ to rotate in the counterclockwise direction. Rotating the bell-crank  40 ′ in the counterclockwise direction pulls the link  74  downwardly, which pivots the cable pulling lever  72  in the clockwise direction, thereby pulling the cable  68 ′ which pivots the hook from the locking position to the unlocking position. With the hook in the unlocking position, the head restraint  18 ′ automatically pivots to the stowed position. As the seat back  14 ′ continues to pivot forwardly, the first arm  46 ′ falls off or disengages with the trigger finger  44 ′ and at the same time the link  74  goes over-center of the bell-crank pivot  42 ′, whereat the torsion spring  86  causes the bell-crank  40 ′ to continue to rotate in the counterclockwise direction until the bell-crank  40 ′ is in the second position with the first arm  46 ′ abutting the lower stop  84 . It is appreciated that the cable  68 ′ is at a maximum pulled state as the link  74  goes over-center of the bell-crank pivot  42 ′ such that continued pivoting of the seat back  14 ′ toward the forwardly folded position does not continue to pull the cable  68 ′. Additionally, since the link  74  is over-center the bell-crank  40 ′ will remain in the second position until the link  74  goes back over-center, and this in turn maintains the hook in the unlocking position. Thus, the bell-crank  40 ′ acts as a lock-out feature because the head restraint  18 ′ cannot be returned to the use position until the hook is returned to the locking position and the hook cannot be returned to the locking position until the bell-crank  40 ′ returns to the first position. 
         [0028]    To return the head restraint  18 ′ to the use position, the seat back  14 ′ is pushed rearwardly to pivot the seat back  14 ′ to the upright position. As the seat back  14 ′ pivots rearwardly, the second arm  48 ′ of the bell-crank  40 ′ engages the trigger finger  44 ′, which causes the bell-crank  40 ′ to rotate in the clockwise direction. Rotating the bell-crank  40 ′ in the clockwise direction pushes the link  74  upwardly, which allows the cable pulling lever  72  to pivot in the counterclockwise direction, thereby releasing the cable  68 ′. As the seat back  14 ′ continues to pivot rearwardly, the second arm  48 ′ falls off or disengages with the trigger finger  44 ′ and at same time the link  74  goes back over-center of the bell-crank pivot  42 ′, whereat the torsion spring  86  causes the bell-crank  40 ′ to continue to rotate in the clockwise direction until the bell-crank  40 ′ is in the first position and the distal end  80  of the cable pulling lever  72  is abutting the upper stop  82 . With the bell-crank  40 ′ in the first position, the cable  68 ′ is fully released, which allows the hook to pivot from the unlocking position to the locking position. With the hook in the locking position, the head restraint  18 ′ can be manually returned to the use position. 
         [0029]    The invention has been described here in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically enumerated within the description.