Abstract:
A recliner assembly provides pivotal movement of a seat back relative to a seat cushion for a vehicle seat. The recliner assembly includes a rotatable rod extending between a first end and a second end. A first recliner is fixedly coupled to the first end of the rod and is operable between a locked condition wherein the seat back is fixed relative to the seat cushion and an unlocked condition wherein the seat back is selectively pivotally adjustable. A second recliner is operatively coupled to the second end of the rod and is operable between the locked condition and the unlocked condition. A bushing is disposed between the second recliner and the rod. The bushing biases the second recliner against the rod to synchronize the first and second recliners to unlock simultaneously. The bushing also provides a lost motion connection to allow the first and second recliners to lock independently.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a recliner assembly for pivotally adjusting a seat back relative to a seat cushion of an automotive vehicle seat. More particularly, the invention relates to a recliner assembly including a spring bushing for synchronizing a pair of disc recliners to unlock simultaneously and providing a lost motion connection allowing the disc recliners to lock independently. 
         [0003]    2. Description of Related Art 
         [0004]    Automotive vehicles include seat assemblies for supporting a seated occupant in the vehicle. The seat assemblies typically include a generally horizontal seat cushion and a generally vertical or upright seat back pivotally connected to the seat cushion by a recliner assembly. The recliner assembly allows selective pivotal adjustment of the seat back relative to the seat cushion between a plurality of reclined positions. Each of the seat cushion and seat back commonly include a rigid frame structure supporting a cellular foam pad that is encased by a fabric trim cover. 
         [0005]    Disc recliners are well known in the vehicle seating art and are commonly used to pivotally connect the seat back to the seat cushion. Typically, disc recliners include a cylindrical outer disc fixedly secured to the seat cushion and a cylindrical inner disc fixedly secured to the seat back and rotatably coupled to the outer disc. Disc recliners further include an internal locking mechanism for locking the inner and outer discs together to thereby maintain the angular position of the seat back relative to the seat cushion. The locking mechanism typically includes an annular rim of teeth on the inner disc and several pawls each with a plurality of teeth. The pawls are movable, either slidingly or pivotally, in a radial direction between an engaged position and a disengaged position. With the pawls in the engaged position, the teeth on the pawls are interlocked or meshingly engaged with the rim of teeth on the inner disc, thus locking the inner and outer discs together and maintaining the angular position of the seat back relative to the seat cushion. When the pawls are moved from the engaged position to the disengaged position, the teeth on the pawls are spaced from the rim of teeth on the inner disc, thus allowing rotation of the inner disc relative to the outer disc and thereby providing adjustment of the seat back relative to the seat cushion. 
         [0006]    The seat assemblies commonly include an inboard disc recliner and an outboard disc recliner which are coupled together by a rod or cross-talk tube so that only one recliner lever or release handle is required to operate the seat back. Typically, the recliner lever is coupled to the cross-talk tube adjacent the outboard recliner. Ideally, when the occupant manipulates the recliner lever to adjust the relative angle of the seat back or other desired operation of the seat back, the inboard and outboard recliners are synchronized and unlock simultaneously. Likewise, when the recliner lever is released the recliners lock simultaneously, preventing further movement of the seat back. 
         [0007]    A problem arises when the prior art seat assemblies are manufactured and assembled. If the inboard recliner is not perfectly aligned with and extending parallel to the outboard recliner, the recliners will not be properly mounted on the cross-talk tube joining the recliners. Improper mounting causes the recliners to bind, increasing the effort required to operate the seat back. In addition, imperfect alignment of the recliners may result in the inboard recliner remaining open or unlocked after the recliner lever is released, thereby holding the outboard recliner unlocked. This situation arises when the recliner lever is released and the teeth on the pawls of the inboard recliner are in tip-to-tip or tooth-to-tooth engagement with the rim of teeth on the inner disc. In this condition, the pawls are prevented from returning to the locked position such that the inboard recliner will remain unlocked, and because the inboard and outboard recliners are joined by the cross-talk tube, the outboard recliner will also remain unlocked. Imperfect alignment is common within normal acceptable build tolerances. 
         [0008]    In International Patent Publication Number WO2006105657 a bushing is operatively connected between a cross-talk tube and a locking mechanism of an inboard recliner. The bushing provides a lost motion connection between the cross-talk tube and the locking mechanism such that imperfect alignment of the inboard and outboard recliners does not allow the inboard recliner, when the locking mechanism is in a tooth-to-tooth condition, to hold the outboard recliner unlocked after the recliner lever is released. In other words, due to the lost motion connection the inboard and outboard recliners can lock independently. 
         [0009]    It is desirable to provide a recliner assembly including an improved lost motion connection or spring bushing coupled between a cross-talk tube and a locking mechanism of an inboard recliner to allow the inboard recliner and an outboard recliner to lock independently and to also synchronize the inboard and outboard recliners to unlock simultaneously. 
       SUMMARY OF THE INVENTION 
       [0010]    According to one aspect of the invention, a recliner assembly is provided for pivotal movement of a seat back relative to a seat cushion for an automotive vehicle seat. The recliner assembly includes a rotatable rod that extends between a first end and a second end. The recliner assembly also includes a first recliner that is fixedly coupled to the first end of the rod. The first recliner is operable between a locked condition wherein the seat back is fixed relative to the seat cushion and an unlocked condition wherein the seat back is selectively pivotally adjustable. The recliner assembly further includes a second recliner that is operatively coupled to the second end of the rod. The second recliner is operable between the locked condition and the unlocked condition. In addition, the recliner assembly includes a bushing that is disposed between the second recliner and the rod. The bushing biases the second recliner against the rod to synchronize the first and second recliners to unlock simultaneously. The bushing also provides a lost motion connection to allow the first and second recliners to lock independently. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    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: 
           [0012]      FIG. 1  is a side view of a seat assembly illustrating pivotal adjustment of a seat back by a recliner assembly according to the invention; 
           [0013]      FIG. 2  is a perspective view of the recliner assembly of  FIG. 1  including a master disc recliner and a slave disc recliner; 
           [0014]      FIG. 3  is an exploded perspective view of the slave disc recliner of  FIG. 2 ; 
           [0015]      FIG. 4  is a perspective view of a fixed plate of the slave disc recliner of  FIG. 3 ; 
           [0016]      FIG. 5  is a perspective view of a rotary plate of the slave disc recliner of  FIG. 3 ; 
           [0017]      FIG. 6  is a perspective view of a cam and pawl arrangement of the slave disc recliner of  FIG. 3 ; 
           [0018]      FIG. 7  is a perspective view of the cam of the slave disc recliner of  FIG. 3 ; 
           [0019]      FIG. 8  is a perspective view of a bushing and cross-talk tube of  FIG. 3 ; 
           [0020]      FIG. 9  is an outer perspective view of the bushing snap-fitted into the cam of  FIG. 3 ; 
           [0021]      FIG. 10  is an inner perspective view of the bushing snap-fitted into the cam of  FIG. 3 ; and 
           [0022]      FIG. 11  is a cross-sectional view taken along lines  11 - 11  of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to the Figures,  FIG. 1  discloses a seat assembly generally shown at  10  for use in an automotive vehicle. The seat assembly  10  includes a seat cushion  12  and a seat back  14  for supporting a seat occupant in the vehicle. Each of the seat cushion  12  and seat back  14  typically include a rigid frame structure for supporting a contoured, foam pad encased by a trim cover as is well known to one skilled in the art. The seat assembly  10  also includes a recliner assembly, generally indicated at  16 , interconnecting the seat cushion  12  and seat back  14  for pivotal movement of the seat back  14  relative to the seat cushion  12  between a plurality of reclined positions. 
         [0024]    Referring to  FIG. 2 , the recliner assembly  16  includes a pair of spaced apart disc recliners. More specifically, the recliner assembly  16  includes a master or outboard disc recliner  18  and a slave or inboard disc recliner  20 . The master  18  and slave  20  recliners are coupled together by a hollow rod or cross-talk tube  22  defining a rotational axis R. Both the master  18  and slave  20  recliners are symmetrically opposite, which minimizes tooling and ultimately costs. The recliner assembly  16  also includes a recliner lever  24  fixedly secured to a first end  26  of the cross-talk tube  22  adjacent the master recliner  18 . The seat occupant manipulates the recliner lever  24  to actuate the recliner assembly  16  in order to adjust the angle of the seat back  14  relative to the seat cushion  12 . 
         [0025]    The master recliner  18  is secured to or integrally formed with the first end  26  of the cross-talk tube  22  such that manipulating the recliner lever  24  actuates the master recliner  18  between a locked condition in which the seat back  14  is prevented from moving relative to the seat cushion  12  and an unlocked condition in which the angle of the seat back  14  can be adjusted relative to the seat cushion  12 . Ideally, the slave recliner  20  actuates between the locked and unlocked conditions simultaneously with the master recliner  18 . However, due to manufacturing tolerances and relative alignment of the master  18  and slave  20  recliners, accommodation must be made to ensure synchronization of the master  18  and slave  20  recliners. Therefore, a spring bushing  28  is disposed between a second or distal end  30  of the cross-talk tube  22  and the slave recliner  20 , as will be described in further detail below. 
         [0026]    Referring to  FIG. 3 , the slave recliner  20  is shown in detail. The slave recliner  20  includes a pair of opposing plates, specifically a fixed plate  32  and a rotary plate  34 . The fixed plate  32  is adapted to be mounted to the seat cushion  12  and the rotary plate  34  is adapted to be mounted to the seat back  14 . The fixed plate  32  and the rotary plate  34  are circumferentially held together by a fastener or retaining ring  36  in a manner well known in the art so that the rotary plate  34  can move or rotate relative to the fixed plate  32  about the rotational axis R. The slave recliner  20  also includes a locking mechanism that can prevent the rotary plate  34  from rotating relative to the fixed plate  32 , and thereby lock the slave recliner  20 . The locking mechanism includes a pair of toothed sliding pawls  38 , a cam  40 , and a pair of torsion springs  42  mounted between the fixed  32  and rotary  34  plates. 
         [0027]    Referring to  FIG. 4 , the fixed plate  32  is generally cup-shaped and includes a circumferentially extending outer flange  44  defining an inner surface or cavity  46 , and a central bore  48 . Positioned in the cavity  46  are a series of islands that define a pair of first guide walls  50  and a pair of second guide walls  51  spaced apart from and opposing the first guide walls  50 . The first  50  and second  51  guide walls cooperate with the pawls  38  to guide the pawls  38  in a radial direction. A pair of diametrically opposed posts  52  are positioned normal to the radial direction of travel of the pawls  38 . 
         [0028]    Referring to  FIG. 5 , the rotary plate  34  is generally cup-shaped and includes a circumferentially extending flange  54  and a central bore  56 . An inner surface of the flange  54  has a series of spaced teeth  58 . The flange  54  is sized to fit within the outer flange  44  of the fixed plate  32 . 
         [0029]    Referring to  FIG. 6 , the pawls  38  are formed in a common shape to each other and are slidably mounted to the fixed plate  32 . Each pawl  38  has linear side surfaces  60 ,  62  substantially parallel to each other and extending along the respective first  50  and second  51  guide walls in the fixed plate  32 . Thus, the pawls  38  can vertically slide or shift in the direction shown by arrow D. An outer peripheral edge  64  of each of the pawls  38  has a convex shape with a series of teeth  66  for releasably meshingly engaging a portion of the teeth  58  on the rotary plate  34 . An inner peripheral edge  68  of each of the pawls  38  has a cam follower surface defined by lobes  70 ,  72  and a release hook  74 . 
         [0030]    Referring to  FIGS. 6 and 7 , the cam  40  is rotatably disposed between the pair of pawls  38  for rotation about the rotational axis R. The cam  40  includes a cam surface defined by a pair of diametrically opposed first lobes  76  and a pair of diametrically opposed second lobes  78 . The first  76  and second  78  lobes are in contact with the respective lobes  70 ,  72  of the pawls  38  when the cam  40  is in a locked position, such that the teeth  66  on the pawls  38  are meshingly engaged with the teeth  58  on the rotary plate  34  and the slave recliner  20  is in the locked condition. Each of the second lobes  78  defines a hook end  80  for engaging the release hook  74  on the pawls  38 . The cam  40  has a degree of free motion wherein the cam  40  rotates without effecting movement of the pawls  38 . As the cam  40  rotates in a clockwise direction (when viewed from  FIG. 3 ) about the rotational axis R and the hook end  80  initially engages the release hook  74 . In this ready position, the cam  40  maintains the pawls  38  in the locked condition. Further rotation of the cam  40  pulls the pawls  38 , such that the teeth  66  on the pawls  38  are disengaged or spaced apart from the teeth  58  on the rotary plate  34  and the slave recliner  20  is in the unlocked condition. 
         [0031]    The cam  40  is always urged in a counterclockwise direction (when viewed from  FIG. 3 ) toward the locked position by the torsion springs  42 . Each spring  42  extends between one of the posts  52  mounted to the fixed plate  32  and a spring receiving portion  82  provided on the cam surface of the cam  40 . The springs  42  are wound in a direction so as to generate a torque urging the cam  40  in the counterclockwise direction toward the locked position. 
         [0032]    Referring to  FIGS. 7 through 11 , the cam  40  includes a specially shaped central bore  84  for receiving the spring bushing  28  therein. In one embodiment of the invention, the spring bushing  28  is made of spring steel and is snap-fitted into the central bore  84 . More specifically, the spring bushing  28  has a sleeve body  85  that extends between an inner end  86  and an outer end  88 . The sleeve body  85  is sized to surround the second end  30  of rod  22 . The inner end  86  of the spring bushing  28  includes a pair of spaced apart and diametrically opposed holding tabs  90  and a pair of spaced apart and diametrically opposed biasing tabs  92 . Biasing tabs  92  are offset 90° from the holding tabs  90 . The holding tabs  90  and the biasing tabs  92 , each has a leg portion and bent foot portion. The outer end  88  of the spring bushing  28  includes a pair of spaced apart guide tabs  94  and a pair of spaced apart and offset retaining tabs  96 . 
         [0033]    The central bore  84  of the cam  40  includes a plurality of recesses reversely symmetrical formed therearound defining a pair of opposing and offset drive surfaces  98 , a pair of opposing guide surfaces  100 , and a pair of opposing and offset retainer surfaces  102 , as shown in  FIG. 7 . The spring bushing  28  is configured to generally complement the central bore  84  and is inserted into the cam  40 . The guide tabs  94  engage the guide surfaces  100  to align the spring bushing  28  within the cam  40 , and the retaining tabs  96  engage the retainer surfaces  102  and include a step  104  to securably and snappingly retain the spring bushing  28  and cam  40  together, as shown in  FIG. 9 . 
         [0034]    Referring to  FIG. 8 , the second end  30  of the cross-talk tube  22  is generally rectangular having a pair of opposed concave sides  106  and a pair of opposed convex sides  108 . The second end  30  of the cross-talk tube  22  is inserted through the spring bushing  28 . The offset biasing tabs  92  at the inner end  86  of the spring bushing  28  springingly engage diametrically opposed concave sides  106 . As the tube  22  rotates, the biasing tabs  92  will engage corners of the respective concave sides  106  of the cross-talk tube  22  at A, as shown in  FIG. 11 , thereby increasing reactionary forces in the direction of arrow F. The reactionary forces bias or preload the cam  40  in the counterclockwise direction such that the drive surfaces  98  of the cam  40  abut diametrically opposite corners of the cross-talk tube  22  at B, as shown in  FIG. 11 . In this ready position, the cam  40  is in the lock position and further rotation will initiate unlocking movement. 
         [0035]    Since the drive surfaces  98  of the cam  40  are biased against the cross-talk tube  22 , the master  18  and slave  20  recliners are synchronized such that rotating the cross-talk tube  22  in the clockwise direction will simultaneously actuate the master  18  and slave  20  recliners. Thus, the spring bushing  28  automatically compensates for differences in orientation between the master  18  and slave  20  recliners. 
         [0036]    The holding tabs  90  engage the respective convex sides  108  of the cross-talk tube  22  to prevent buzz, squeak, and rattle between the cross-talk tube  22  and the spring bushing  28 . 
         [0037]    In operation, when it is desired to adjust the angular position of the seat back  14  relative to the seat cushion  12  the seat occupant manipulates the recliner lever  24 . Lifting the recliner lever  24  causes the cross-talk tube  22  to rotate in the clockwise direction (when viewed from  FIG. 2 ) actuating the master recliner  18  from the locked condition to the unlocked condition. At the same time, referring to the slave recliner  20 , the second end  30  of the cross-talk tube  22  rotates in the clockwise direction causing the cam  40  to also rotate in the clockwise direction toward the unlocked position. As the cam  40  rotates in the clockwise direction, the hook end  80  of the second lobes  78  engages the release hook  74  on the pawls  38 , pulling the pawls  38  inward. When the cam  40  is in the unlocked position the teeth  66  on the pawls  38  are disengaged from the teeth  58  on the rotary plate  34  and the slave recliner  20  is in the unlocked condition. The angular position of the seat back  14  can now be freely adjusted. 
         [0038]    Once the desired position of the seat back  14  is obtained the seat occupant releases the recliner lever  24 . Releasing the recliner lever  24  allows the master recliner  18  to automatically actuate from the unlocked condition to the locked condition, which causes the cross-talk tube  22  to rotate in the counterclockwise direction (when viewed from  FIG. 2 ). At the same time, referring to the slave recliner  20 , the springs  42  urge the cam  40  to rotate in the counterclockwise direction toward the locked position. As the cam  40  rotates in the counterclockwise direction, the hook end  80  of the second lobes  78  disengages from the release hook  74  on the pawls  38  and the first  76  and second  78  lobes of the cam  40  abut the respective lobes  70 ,  72  of the pawls  38 , pushing the pawls  38  outward. When the cam  40  is in the locked position the teeth  66  on the pawls  38  are meshingly engaged with the teeth  58  on the rotary plate  34  and the slave recliner  20  is in the locked condition. The seat back  14  can no longer be pivotally adjusted. 
         [0039]    Due to manufacturing tolerances and relative alignment of the master  18  and slave  20  recliners, it is possible that once the recliner lever  24  is released the master recliner  18  will return to the locked condition while the slave recliner  20  will remain in the unlocked condition. For example, the slave recliner  20  remains in the unlocked condition when the tips of the teeth  66  on the pawls  38  abut the tips of the teeth  58  on the rotary plate  34 . This is referred to as a tip-to-tip or tooth-to-tooth condition. In the tooth-to-tooth condition, since the teeth  66  on the pawls  38  are not meshingly engaged with the teeth  58  on the rotary plate  34 , the cam  40  is not in the locked position. However, because the spring bushing  28  is disposed between the cross-talk tube  22  and the cam  40 , the biasing tabs  92  of the spring bushing  28  provide a lost motion connection allowing the cross-talk tube  22  to continue to rotate in the counterclockwise direction without the cam  40  rotating in the counterclockwise direction. The cross-talk tube  22  continues to rotate in the counterclockwise direction until the master recliner  18  is in the locked condition. The reactionary forces F then urge the cam  40  to rotate in the counterclockwise direction until the drive surfaces  98  of the cam  40  abut the cross-talk tube  22  and the slave recliner  20  is in the locked condition. 
         [0040]    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.