Abstract:
A head restraint assembly is provided with a first guide member mounted proximate to a vehicle seat back. A second guide member is mounted to the first guide member for translation along the first guide member. A locking mechanism is mounted to the second guide member in cooperation with the first guide member for locking the second guide member relative to the first guide member. The first and second guide members are connected by at least one spherical bushing. A torsion spring is connected to the first guide member and oriented about the second guide member for locking the second guide member relative to the first guide member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application Ser. No. 61/758,324 filed Jan. 30, 2013, the disclosure of which is hereby incorporated in its entirety by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments relate to adjustable head restraint assemblies. 
       BACKGROUND 
       [0003]    An adjustable head restraint assembly is disclosed in Low et al. U.S. Pat. No. 7,073,863 B1, which issued on Jul. 11, 2006. 
       SUMMARY 
       [0004]    According to at least one embodiment, a head restraint assembly is provided with a first guide member mounted proximate to a vehicle seat back. A second guide member is mounted to the first guide member for translation along the first guide member. A locking mechanism is mounted to the second guide member in cooperation with the first guide member for locking the second guide member relative to the first guide member. The first and second guide members are connected by at least one spherical bushing. 
         [0005]    According to at least another embodiment, a head restraint assembly is provided with a first guide member mounted proximate to a vehicle seat back. A second guide member is mounted to the first guide member for translation along the first guide member. A torsion spring is connected to the first guide member and oriented about the second guide member for locking the second guide member relative to the first guide member. At least one spherical bushing is mounted about the second guide member and received within the first guide member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a side elevation view of an adjustable head restraint assembly according to an embodiment; 
           [0007]      FIG. 2  is a partial section view of the head restraint assembly of  FIG. 1 , illustrating a guide assembly and a locking mechanism; 
           [0008]      FIG. 3  is a partial front perspective view of the head restraint assembly of  FIG. 1 ; 
           [0009]      FIG. 4  is a partial rear perspective view of the head restraint assembly of  FIG. 1 ; 
           [0010]      FIG. 5  is a top view of the locking mechanism of  FIG. 2 ; 
           [0011]      FIG. 6  is an exploded perspective view of the locking mechanism of  FIG. 2 ; 
           [0012]      FIG. 7  is an enlarged perspective view of an end of the guide assembly of  FIG. 2 ; 
           [0013]      FIG. 8  is a partially exploded perspective view of the head restraint of  FIG. 1 ; 
           [0014]      FIG. 9  is a partial perspective view of the head restraint of  FIG. 1 ; 
           [0015]      FIG. 10  is a partially exploded perspective view of the guide assembly of  FIG. 2 ; 
           [0016]      FIG. 11  is a partially exploded side view of the guide assembly of  FIG. 2 ; 
           [0017]      FIG. 12  is a side view of the guide assembly of  FIG. 2 ; 
           [0018]      FIG. 13  is a schematic view of the guide assembly of  FIG. 2 , illustrated in alignment; and 
           [0019]      FIG. 14  is another schematic view of the guide assembly of  FIG. 2 , illustrated in misalignment. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0021]    Referring to  FIGS. 1-4 , a movable head restraint assembly is illustrated and referenced generally by numeral  10 . The head restraint assembly  10  is provided adjacent a seatback of a vehicle seat; and may be mounted directly to the vehicle seat or directly to the vehicle body adjacent the seatback for supporting the head of an occupant. The seat assembly may be for a vehicle such as a car, truck, aircraft, watercraft, or the like. The movable head restraint assembly  10  is illustrated including a head restraint  12  provided upon a support post  14 . 
         [0022]    The support post  14  maybe fixed relative to the vehicle or the vehicle seat back. The support post  14  may be received within a guide sleeve for upright adjustment relative to the seatback. The support post  14  may have any suitable configuration. For example, one or more support posts  14  may extend from the head restraint  12 . Moreover, the support post  14  may be formed integrally with another support post  14  with a crossbar  16  interconnecting and spacing apart the support posts  14 . The support posts  14  may be made of any suitable material or materials such as a metal or metal alloy. 
         [0023]    The head restraint  12  may include a trim cover (not shown) for enclosing foam (also not shown), a housing  18 , and a locking mechanism  20 . A manual button assembly  22  extends from the housing  18  in the trim cover for manual actuation for disengaging the locking mechanism  20 . The button assembly  22  is illustrated oriented to be manually actuated by being pressed in a lateral direction of the head restraint  12 . Pressing the button assembly  22  releases the locking mechanism  20  and permits movement of the head restraint  12  relative to the support posts  14  in a fore and aft direction, which may be horizontal. In  FIGS. 1-4 , the head restraint  12  is illustrated at a limit in one direction, the aft direction, relative to the vehicle. Thus, by depressing the button assembly  22 , the occupant may move the head restraint  12  in the fore direction from the position depicted, or to multiple, non-incremental positions therebetween. 
         [0024]    With reference specifically to  FIGS. 3 ,  5  and  12 , a frame  24  is mounted to the crossbar  16  for supporting the head restraint  12 . The frame  24  supports a pair of nuts  26 ,  28 , ( FIGS. 1 ,  2 ,  4 - 6  and  8 - 14 ) which are each threaded into the frame  24 . The nuts  26 ,  28  each retain a bushing  30 ,  32  ( FIGS. 2 ,  5 ,  6 , and  9 - 14 ) with the locking mechanism  20  oriented therebetween. 
         [0025]    The housing  18  includes a pair of shells  34 ,  36 , which are sized to mate and retain the components of the head restraint  12  therein. The upper shell  36  is illustrated removed in  FIGS. 3 and 4 . Both shells are illustrated removed in  FIGS. 5-12 . A guide shaft  38  extends in a fore and aft direction of the head restraint  12 . The guide shaft  38  is mounted to the shells  34 ,  36  by a pair of brackets  40 ,  42 , which are retained within the shells  34 ,  36 . Referring again to  FIGS. 2-4 , a through bolt  44  extends through the upper shell  36 , the bracket  40 , the nut  26  and bushing  30 , the locking mechanism  20 , the nut  28  and bushing  32 , the bracket  42 , the upper shell  36  again, and a nut  46 . The guide shaft  38  cooperates with the bushings  30 ,  32  for translation of the guide shaft  38 , and consequently the head restraint  12 , relative to the bushings  30 ,  32  and the support posts  14  for adjustment of the head restraint  12  relative to the support posts  14 . 
         [0026]    The locking mechanism  20  includes a torsion spring  48  ( FIGS. 2 ,  5  and  6 ) oriented about the guide shaft  38  and sized to tighten about the guide shaft  38  and lock to a position upon the guide shaft  38 . Each end of the torsion spring  48  is connected to a lever  50 ,  52 , ( FIGS. 2-6  and  10 - 12 ) which are each also pivotally connected to the guide shaft  38  and are oriented between the bushings  30 ,  32 . Counter rotation of the levers  50 ,  52  expands the torsion spring  48 , thereby unlocking the torsion spring  48  from the guide shaft  38  for permitting movement of the guide shaft  38  and consequently the head restraint  12  relative to the support post  14 . 
         [0027]    The button assembly  22  ( FIGS. 1 and 3 ) includes a bezel  54  mounted to the shells  34 ,  36 . A button  56  is mounted in the bezel  54  for linear translation, which pivots a lever  58  ( FIG. 3 ) that is pivotally connected to the lower shell  34 . Referring now to  FIGS. 3 and 4 , a cable  60  is connected to the lever  58  and extends to a boss  62  ( FIG. 3 ) that is provided upon the lower shell  34 . A cable sheath  64  extends from the boss  62  to a boss  66  ( FIG. 4 ) on the lever  52 . The cable  60  extends through the sheath  64  and extends to the lever  50 . The pivoting of the lever  58  downward, pulls the cable  60  within the sheath  64  thereby converging the levers  50 ,  52  for counter rotation of the levers  50 ,  52  relative to each other. This counter rotation expands the torsion spring  48  permitting adjustment of the guide shaft  38  within the torsion spring  48 . 
         [0028]    By providing only one guide shaft  38 , binding is eliminated that is associated with tolerances and misalignments when utilizing multiple guide shafts. Additionally, utilization of the spherical bushings  30 ,  32  also permits flexibility for compliance with tolerances and misalignments. By utilization of the guide shaft  38  with the torsion spring  48 , multiple adjustment positions are permitted that are not limited to specific notches or detents. This positional flexibility is often referred to as infinitely adjustable. 
         [0029]    With reference to  FIGS. 2-4 ,  8  and  9 , a drum spring return mechanism  68  is supported upon the frame  24  with a distal end  70  extending from the mechanism  68  and connecting to a hook  72  on the bracket  42 . The drum spring mechanism  68  provides a constant force on the bracket  42  and consequently the head restraint  12  to bias the head restraint  12  to a forward-most position when unlocked from the locking mechanism  20 . Thus, the head restraint assembly  10  provides one-handed operation for adjustment in the fore and aft direction. The occupant does not need to pull the head restraint  12  forward. By unlocking the locking mechanism  20 , the head restraint  12  travels to a forward position. The occupant can move the head restraint  12  rearward, when the locking mechanism is unlocked by pressing his or her head rearward against the head restraint in order to obtain a desired position. 
         [0030]    With reference now to  FIGS. 2 ,  5  and  6 , a pair of washers  74 ,  76  is provided about the guide shaft  38  with the torsion spring  48  between the washers  74 ,  76 . The washers  74 ,  76  are each received within a bore  78 ,  80  within each of the levers  50 ,  52 . The spherical bushings  30 ,  32  each include an aperture  82 ,  84  formed through the bushing  30 ,  32 . The apertures  82 ,  84  each have a constant diameter sized for a clearance fit over the guide shaft  38 . 
         [0031]    In  FIGS. 2 ,  5 - 8  and  10 - 12 , the nuts  26 ,  28  are illustrated in greater detail. Each of the nuts  26 ,  28  include a threaded body  86  for threaded in engagement during installation into the frame  24 . A flange  88  is provided on the body  86  for providing a limit of axial translation during installation into the frame  24 . A series of wrench flats  90 , such as a hexagonal bolt head, are provided outboard of the flange  88 . Each of the nuts  26 ,  28  include a socket  92  within the body  86  for receiving the corresponding bushing  30 ,  32  therein. The socket  92  may have any suitable shape for receiving the corresponding bushing  30 ,  32 . For example, the socket  92  may be hemispherical, conical or the like. A clearance aperture  94  is formed through the bolt head  90  that is greater than a diameter of the guide shaft  38  for permitting clearance to the guide shaft  38 . The nuts  26 ,  28  may be formed from a structural plastic, such as nylon with fillers for withstanding applicable loading, minimizing friction with the bushings  30 ,  32 , and for withstanding the environment within a vehicle. 
         [0032]    With reference now to  FIGS. 8 ,  10  and  12 , one of the nuts  26  is illustrated during installation to the frame  24 . The frame  24  includes a pair of helically stamped apertures  96 ,  98  for receiving the threaded bodies  86  of the nuts  26 ,  28 . The threaded engagement permits installation and adjustment of the nuts  26 ,  28  into the frame  24 . The bodies  86  may be molded oversized relative to the frame apertures  96 ,  98  for providing a friction fit for resisting loosening after installation. The nuts  26 ,  28  permit attachment without additional fasteners. 
         [0033]    The utilization of the spherical bushings  30 ,  32  permits adjustment along the guide shaft  38  without binding caused by unevenly applied forces upon the head restraint  12 . The spherical bushings  30 ,  32  also compensate for tolerances. The spherical bushings  30 ,  32  in combination with the torsion spring  48  and levers  50 ,  52  remove many components and complexities associated with prior art guide assemblies and locking mechanisms. The linear movement is provided without a linkage thereby removing moving parts that add to weight, cost, buzz, squeak and rattle. 
         [0034]    With fore/aft adjustment executed along a single horizontal guide shaft  38 , loading that is offset from an axis of the shaft  38  can exaggerate fore/aft free-play. Stack-up of the components assembled along the guide shaft  38  also exaggerate fore/aft free-play. Resistance to fore/aft adjustment may be present due to misalignment. The potential exaggerated free-play and resistance is minimized by the spherical bushings  30 ,  32 . 
         [0035]      FIGS. 13 and 14  are schematic views of the nuts  26 ,  28 , the spherical bushings  30 ,  32 , and the guide shaft  38 . In  FIG. 13 , all are aligned for smooth adjustment of the head restraint  12  due to translation of the guide shaft  38  relative to the nuts  26 ,  28 .  FIG. 14  illustrates how misalignment is compensated by pivoting of the spherical bushings  30 ,  32  within the sockets  92  for permitting free linear translation of the shaft  38  relative to the bushings  30 ,  32 . The clearance apertures  94  are sized to accommodate acceptable angular tolerances or misalignments to prevent the guide shaft  38  from interfering with the nuts  26 ,  28 . 
         [0036]    While various embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.