Abstract:
A head restraint ( 20 ) having a front surface ( 22 ) for supporting the head of the occupant seated on the seat assembly ( 10 ) is pivotally coupled to the upper portion ( 15 ) of the seat back ( 12 ) and moveable relative to the seat back between a plurality of angled head supporting positions (A) and a forwardly folded stowed position (B) defined by the front surface ( 22 ) of the head restraint ( 20 ) being generally perpendicular to the front surface ( 17 ) of the seat back ( 12 ). The seat assembly further includes a mechanism operatively interconnecting the head restraint to the seat back for providing automatic and continuous pivotal movement of the head restraint between one of the head supporting positions and the stowed position in response to pivotal adjustment of the seat back between one of the reclined seating positions and the forwardly folded positions.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The subject invention relates to a vehicle seat assembly having a self positioning head restraint assembly, and more particularly, to a self positioning head restraint assembly for automatically and continuously adjusting the angular position of a head restraint in response to pivotal movement of a seat back relative to a seat cushion. 
   2. Description of the Related Art 
   Automotive vehicles include vehicle seat assemblies for supporting an occupant in a vehicle. The seat assemblies comprise a seat cushion and a seat back, typically pivotally mounted to the seat cushion by a recliner mechanism. The seat back is often pivotal between a plurality of reclined seating positions and a forwardly folded flat position. The seat assemblies also commonly comprise a head restraint coupled to the seat back for supporting the seat occupant&#39;s head. Typically, the height or pivotal displacement of the head restraint may be adjusted, either manually or by power actuation, regardless of the position of the seat back. 
   It remains desirable to provide a mechanism for automatically and continuously adjusting the angular position of the head restraint relative to the seat back in response to the pivotal adjustment of the seat back. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a seat assembly comprising a seat cushion having front and rear portions, and a seat back having upper and lower portions. The seat back is operatively connected at the lower portion to the rear portion of the seat cushion for pivotal movement relative to the seat cushion between a plurality of reclined seating positions and a forwardly folded flat position. The seat back further includes a front surface for supporting the back of an occupant seated on the seat assembly. A head restraint having a front surface for supporting the head of the occupant seated on the seat assembly is pivotally coupled to the upper portion of the seat back and moveable relative to the seat back between a plurality of angled head supporting positions and a forwardly folded stowed position defined by the front surface of the head restraint being generally perpendicular to the front surface of the seat back. The seat assembly further includes a mechanism operatively interconnecting the head restraint to the seat back for providing automatic and continuous pivotal adjustment of the head restraint to one of the head supporting positions in response to pivotal adjustment of the seat back to one of the reclined seating positions. The mechanism further provides automatic and continuous pivotal movement of the head restraint between one of the head supporting positions and the stowed position in response to pivotal adjustment of the seat back between one of the reclined seating positions and the forwardly folded positions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
       FIG. 1  is a schematic side view of an automotive seat assembly incorporating a self positioning head restraint assembly, according to the subject invention; 
       FIG. 2  is a perspective view of the seat assembly incorporating the self positioning head restraint assembly; 
       FIG. 3  is a side view of the seat assembly with a seat back in a generally upright seating position; 
       FIG. 4  is a side view of the seat assembly with the seat back in a fully reclined seating position; 
       FIG. 5  is an enlarged side view of a portion of a mechanism for adjusting the angular position of the head restraint with the seat back in the fully reclined seating position; 
       FIG. 6  is an enlarged side view of a portion of the mechanism for adjusting the angular position of the head restraint with the seat back in a forwardly folded-flat position; 
       FIG. 7  is a side close-up view of the rear and lower portion of the seat assembly with the seat back in the forwardly folded-flat position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the Figures wherein like numerals indicate like or corresponding parts through the several views;  FIG. 1  discloses a seat assembly  10  for use in an automotive vehicle. The seat assembly  10  includes a generally horizontal seat cushion assembly  11  and a seat back  12  assembly for supporting an occupant on the seat  10 . The seat cushion  11  has opposite and spaced apart front and rear portions  13 ,  14 . The seat back  12  has opposite and spaced apart upper and lower portions  15 ,  16 . The seat back  12  further has a front surface  17  for supporting the back of an occupant supported in the seat assembly  10 . The seat back  12  is operatively interconnected at its lower portion  16  to the rear portion  14  of the seat cushion  11  by a pair of synchronized recliner mechanisms  30 ,  31 . The recliner mechanisms  30 ,  31  allow pivotal adjustment of the seat back  12  about a first pivot axis  24  between a plurality of reclined seating positions, as illustrated at A in  FIG. 1 . The recliner mechanisms  30 ,  31  further allows pivotal movement of the seat back  12  about a second pivot axis  26  from one of the reclined seating positions A to a forwardly folded flat position, as illustrated at B in  FIG. 1 . Described in detail below, the seat assembly  10  further includes a head restraint  20  operatively interconnected to the upper portion  15  of the seat back  12  and having a front surface  22  for supporting the head of an occupant. 
   Referring to  FIG. 2 , the seat back  12  comprises a seat back frame  40  having spaced apart and generally parallel side members  42 ,  44 . Each of the side members  42 ,  44  have opposite upper and lower ends  46 ,  48 . An upper cross member  50  extends between the upper ends  46  of each of the side members  42 ,  44 . First and second recliner brackets  52 ,  54  are fixedly attached to the lower ends  48  of each of the side members  42 , 44 , respectively, by any conventional means, such as welding or bolting. A dump pivot stop  56  extends outwardly from each of the first and second recliner brackets  52 ,  54 . 
   Each of the recliner mechanisms  30 ,  31  include an upper portion  32  pivotally assembled to a lower portion  33  by a pivot pin  34 , defining the first pivot axis  24 . The upper portions  32  of each of the recliner mechanisms  30 ,  31  are pivotally assembled to the first and second recliner brackets  52 ,  54 , respectively, by a pivot pin  35 , thus defining the second pivot axis  26 . The upper portions  32  of each of the recliner mechanisms  30 ,  31  further include an arcuate slot  36  for slidably guiding the dump pivot stops  56  of each of the first and second recliner brackets  52 ,  54 , respectively. The arcuate slot  36  has first and second ends  37 ,  38  defining the range of travel for the seat back  12  when the seat back  12  is pivoted about the second pivot axis  26  between one of the reclined seating positions A and the forwardly folded-flat position B. The dump pivot stop  56  is releasably lockable against either of the first and second ends  37 ,  38  of the arcuate slot  36 . Additionally, the upper portion  32  is selectively lockable with the lower portion  33  for allowing pivotal adjustment of the seat back  12  about the first pivot axis  24  in one of the reclined seating positions, wherein the dump pivot stop  56  is lockingly held against the first end  37  of the arcuate slot  36 . Further detailed description and operation of the recliner mechanisms  30 ,  31  is fully set forth in U.S. Pat. No. 5,558,403 issued Sep. 24, 2000, which is incorporated herein by reference in its entirety. 
   Referring to  FIGS. 2 and 3 , the seat assembly  10  further provides a mechanism for automatically and continuously adjusting the angular disposition of the head restraint  20  about a third pivot axis  28  relative to the seat back  12  in response to pivotal movement of the seat back  12  relative to the seat cushion  11 . More specifically, a pair of spaced apart pivot brackets  60 ,  62  are fixedly attached to the upper cross member  50 . A cylindrical shaft  63  is rotatably journaled to each of the pivot brackets  60 ,  62  defining the third pivot axis  28 . A pair of spaced apart head restraint guide posts  64 ,  66  extend generally upwardly from the cylindrical shaft  63  in front of the upper cross member  50  for slidably receiving the head restraint  20 . An arm  68  extends radially from the cylindrical shaft  63 . The head restraint  20  is pivotal relative to the seat back  12  between a plurality of head supporting positions as shown in  FIG. 1  and a stowed position as shown in  FIG. 6 . 
   An eccentric cam plate  70  is rotatably connected to the first recliner bracket  52  by a pivot pin  72 . A guide slot  74  is formed in the cam plate  70 . A control rod  80  having upper and lower ends  82 ,  84  extends generally through the seat back  12  between the head restraint  20  and the cam plate  70 . The upper end  82  of the rod  80  is pivotally attached to the distal end of arm  68 . The lower end  84  of the rod  80  is slidably engaged with the slot  74  of the cam plate  70 . A cam link  86  interconnects the cam plate  70  to the seat cushion  11 . Specifically, the cam link  86  has a first end  87  pivotally assembled to the cam plate  70  and a second end  88  pivotally assembled to the rear portion  14  of the seat cushion by any suitable means, such as by a pin, rivet, or bolt. An extension bracket  90  is fixedly attached to the first recliner bracket  52 . A control link  92  having first and second ends  94 ,  96  interconnects the lower end  84  of the rod  80  to the extension bracket  90 , wherein the first end  94  is pivotally attached to the extension bracket  90  and the second end  96  is pivotally attached to the lower end  84  of the rod  80 . 
   Referring to  FIGS. 3-7 , in operation, the angular position of the head restraint  20  relative to the seat back  12  is a function of the angular position of the seat back  12  relative to the seat cushion  11 . That is, as the seat back  12  is pivotally reclined (in the clockwise direction as shown) from the upright seating position, shown in  FIGS. 1-3 , to a reclined position (towards the fully reclined position shown in  FIG. 4 ) it is desirable to pivot the head restraint  20  relative to the seat back  12  (in the counterclockwise direction as shown) and closer to the occupant&#39;s head for further support thereof. Specifically, when the angular position of the seat back  12  relative to the seat cushion  11  is locked by the recliner mechanisms  30 ,  31 , a corresponding angular position of the cam plate  70  relative to the seat back  12  is maintained by the cam link  86  and in turn, a corresponding position of the lower end  84  of the rod  80  within the slot  74  of the cam plate  70  is maintained by the control link  92 . The control link  92  prevents the lower end  84  from sliding freely within the guide slot  74  of the cam plate  70 . By this arrangement, the angular position of the head restraint  20  is a function of the angular position of the seat back  12 . 
   When the seat back  12  is adjusted rearwardly, for example from a generally upright seating position, shown in  FIG. 3 , to a fully reclined seating position shown in  FIGS. 4 and 5 , the cam link  86  causes the cam plate  70  to pivot counterclockwise relative to the seat back  12  about the pivot pin  72 . As best shown in  FIG. 5 , the control link  92 , in turn, causes the lower end  84  of the rod  80  to slide generally clockwise within the slot  74  from a first position D which corresponds to the generally upright seating position to a second position E which corresponds to the fully reclined position. With the lower end  84  of the rod  80  in either the first position D or the second position E, the head restraint  20  is disposed linearly relative to the seat back  12  wherein the front surface  17  of the seat back  12  and the front surface  22  of the head restraint  20  form a generally flat, or planar, occupant supporting surface. 
   As best viewed in  FIGS. 5 and 7 , the radial distance of the slot  74  from the pivot pin  72  increases between the first and second positions D, E forming a bump  75 . As the seat back  12  is pivoted between the generally upright seating position and the fully reclined seating position, the lower end  84  of the rod  80  slides over the bump  75  in the slot  74  thereby causing the rod  80  to pull the head restraint  20  pivotally forward relative to the seat back  12 . The forward pivoting of the head restraint  20  upon the pivoting movement of the seat back  12  from the upright seating position to any of the reclined seating positions automatically and continuously maintains the optimal angle between the head restraint  20  and seat back  12  and thus the distance to the seat occupant&#39;s head for support thereof. The opposite motion occurs when the seat back  14  is returned from the fully reclined position to the upright seating position. Therefore, the mechanism automatically and continuous adjusts and optimizes the position of the head restraint  20  relative to the seat back, and occupant&#39;s head, in response to pivotal movement of the seat back  12 . 
   When the seat back  12  is adjusted to the forwardly folded-flat position B, shown in  FIGS. 6 and 7 , the cam link  86  causes the cam plate  70  to pivot clockwise relative to the seat back  12  about the pivot pin  72 . In turn, the control link  92  causes the lower end  84  of the rod  80  to slide generally counterclockwise towards a portion F in the slot  74  having the greatest radial distance from the pivot pin  72 . The rod  80  pulls the head restraint  20  pivotally forward, or counterclockwise as shown, relative to the seat back  12  until the head restraint  20  is disposed generally perpendicular to the seat back  12 . This allows the head restraint  20  to clear any obstructions in front of the seat assembly  10  typically present in a vehicle setting, such as a dashboard or another seat. 
   The amount and direction of pivotal movement of the head restraint  20  obtained in response to pivotal movement of the seat back  12  can be tailored to meet the requirements of a particular seating application by modifying the dimensions and pivot locations of the cam plate  70 , the cam link  86 , the control link  92 , and the arm  68 . For example, the bump  75  in the slot  74  can be decreased or increased in its prominence relative to the first and second positions D, E to increase or decrease, respectively, the amount of forward motion of the head restraint  20  when the seat back  12  is pivoted between the generally upright seating position and the fully reclined seating position. 
   The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of 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 practised other than as specifically described.