Abstract:
An adjustable head restraint assembly for enabling a head restraint pad ( 18 ) to be adjustably and lockably positioned with respect to a motor vehicle seatback ( 14 ) so that the head restraint remains in an adjusted position during a crash sequence after being set by a user. Associated with the head restraint pad is a pair of posts ( 20 ) that are provided with notches ( 52 ) for adjustment and one or more square securement notches ( 94 ) to prevent unintended separation of the head restraint pad ( 18 ) from the seatback ( 14 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a head restraint assembly for motor vehicle seats for enabling a head restraint pad to be moved with respect to a motor vehicle seat. 
     2. Background Art 
     Motor vehicle seats typically include a head restraint pad mounted to the seat for comfort and safety of the passenger. The head restraint pad is mounted on one or two posts which are inserted into guide sleeves affixed to the seat. The posts typically include retainer notches which allow the head restraint pad to be vertically adjustable. 
     U.S. Pat. No. 4,854,642 to Hoover Universal, Inc., discloses a head restraint guide assembly having a bushing installed within the seatback for receiving the head restraint pad posts. The head restraint bushing includes extending legs with ramp surfaces so that when the bushing is inserted within the seatback, the legs are resiliently deflected and become locked into place when the installed position is reached. The head restraint post passes through the bushing and has a number of notches which provide detents. A detent lug carried by the bushing engages the detent notches and is resiliently biased against the post. The detent notches are provided with cam surfaces, enabling the head restraint to be raised and lowered to and past the detent positions. The lowermost notch forms a retainer notch with a radial wall which prevents complete removal of the head restraint. A leaf spring actuator can be depressed from outside of the seatback and acts on the detent lug to deflect it out of engagement with the detent notches, thereby enabling withdrawal of the head restraint assembly. 
     In order to remove the head restraint post, a downward force must be applied to the actuator by a tool such as a screwdriver, causing the lug to move out of engagement with the retainer notch. 
     U.S. Pat. No. 6,099,077 discloses a head restraint assembly for a motor vehicle. It is commonly owned with the present application and is incorporated herein by reference. That reference discloses actuator springs within a button subassembly that may become over-stressed because their deflection is relatively unconstrained over repeated use. The invention disclosed in U.S. Pat. No. 6,099,077 solves many of these problems. 
     SUMMARY OF THE INVENTION 
     One difficulty with such conventional approaches is associated with the risk of over-stressing a leaf spring present in a drawer or actuator portion of a head restraint assembly. Accordingly, it would be desirable to limit movement of the leaf of a spring so as to avoid over-stressing it, thereby ensuring that the spring always returns to its undeflected position. 
     Additionally, it would be desirable to provide a means to satisfy requirements mandated by a regulatory authority or by a customer including a feature which precludes inadvertent removal of the head restraint assembly from the seatback. 
     According to the present invention, an improved head restraint assembly is provided for enabling a head restraint pad to be lockably positioned with respect to a motor vehicle seatback. The head restraint pad includes at least one post connected to and supporting the head restraint pad. One or more of the posts associated with a restraint pad have at least one retainer notch for vertically adjusting the height of the head restraint pad. The same one post or another of the at least one posts has a square securement notch positioned below the lowermost of the retainer notches. The square securement notch serves to secure the post firmly in relation to the vehicle seatback so that it may not be readily removed therefrom unless a special tool is used. 
     A tubular bushing is mounted to the seat and has an inside bore sized for receiving the at least one post. The tubular bushing has a head outside the seat and the head has a socket with an open outside end. 
     A button subassembly is insertable into the open outside end of the socket. The button subassembly locks one of the posts in relation to the tubular bushing and seatback. This assembly has a drawer portion having a leading face and a central portion. The central portion has an aperture through which one of the posts extends. Deployed upon the leading face of the drawer portion is a spring or actuator. The actuator is movable between a forward actuated position in which the actuator is disengaged from any notch in the post and a rearward position to which the actuator is biased. In the forward position, deflection of a leaf of the actuator is limited either by a stop that is also provided by the actuator, or by a constraint imposed by a guide defined upon a rail (not shown). In the rearward position, the actuator engages a notch in the post after the button subassembly is released or snap/slot on guide. 
     The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a motor vehicle seat of the type having a separate adjustable head restraint assembly; 
     FIG. 2 is an exploded view of the button subassembly of the head restraint assembly according to the present invention; 
     FIG. 3 is a longitudinal cross-sectional view of the head restraint assembly of FIG. 2, depicting engagement of the actuator with a notch in a post after the button subassembly is released; 
     FIG. 4 depicts two of the posts connected to and supporting the head restraint pad—in this case, the right-hand post having four retainer notches, the left-hand post having a square securement notch; 
     FIG. 5 is a perspective view of the spring or actuator; 
     FIG. 6 is a plan view of the button subassembly before the drawer portion is slid inwardly into the socket, the actuator lying in its natural, biased position; and 
     FIG. 7 resembles FIG. 6, except that the drawer portion is in its forwardmost position and the actuator is moved so as to be disengaged from a notch in the post. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 1, there is shown a perspective view of a motor vehicle seat  10  having a bottom cushion  12  and a seatback  14 . A head restraint assembly including a pad  18  is supported by the seatback  14 . The assembly has a pad  18  and a pair of downwardly extending mounting posts  20 . 
     FIGS. 2 through 7 illustrate various details of the head restraint assembly  16 . The head restraint assembly enables the pad  18  to be moved inwardly and outwardly in relation to the motor vehicle seat  10 . The seatback includes at least one tubular bushing  22 , preferably made of plastic, as depicted in U.S. Pat. No. 6,099,077 which is incorporated herein by reference. Preferably, one tubular bushing  22  is provided for each post  20 . Each tubular bushing  22  has an inside bore  24  for receiving the post  20 . The bushing  22  further includes a head  26  formed at the upper end thereof which engages the outside of the seatback  14  when mounted to the seat  10 . Preferably the seatback  14  includes a frame member  28  having an opening  30  larger than the tubular bushing  22  for receiving at least a portion of the tubular bushing  22  (FIG.  2 ). 
     Continuing with reference to FIGS. 2-3, the head  26  of the bushing  22  has a socket  32  exposed to the bore  24  at a first inner end  34 , and outwardly accessible at a second end  36 . A button subassembly  38  having an insertable end  37  is insertable into socket  32  through the accessible second end  36 . The button subassembly  38  includes an actuator or spring  40  (FIGS.  2  and  5 - 7 ) located on one side of the bore  24  proximate the leading face or insertable end  37 . A drawer portion  42  is located on the opposite end of the button subassembly from the insertable end. The button subassembly has a central portion  39  through which the post  20  extends. 
     In the preferred embodiment, the drawer portion  42  is provided with a leading face having at least one protrusion  44  (FIG. 2) insertable into at least one aperture  46  formed in the spring  40 , thereby removably connecting the spring  40  and the drawer  42 . 
     Additionally, the button subassembly  38  is configured to conform to the head  26  at the accessible second end  36  in the illustrated arrangement so that a flush engagement results when the actuator portion  42  is moved inwardly with respect to the head  26 . 
     Further, in the preferred arrangement, as best shown in FIG. 5, the spring  40  is provided with a crimped section that provides a tongue or saddle  48  and a leaf  50 . Upon insertion of the button subassembly  38 , the spring  40  is positioned within the bore  24 . The leaf  50  contacts the first inner end  34  of the socket  32 . The drawer  42  is positioned on the outer opposite end of bore  24  exposed at the accessible second end thereof. 
     The operation of button subassembly  38  may be understood upon continuing reference to FIGS. 2-7. At least one of the posts  20  is formed with at least one V- or U-shaped retainer notch  52  on its exterior surface (FIG.  4 ). When more than one retainer notch  52  is provided, they are preferably aligned on one side of post  20 . The crimped section  48  is biased into alignment with the associated notch  52  provided along post  20 . 
     The head restraint pad  18  may be moved up or down with respect to the seat  10  by moving drawer  42  into the socket  32  with the push of a finger. This action compresses the leaf  50  of the spring  40  and moves the crimp  48  out of alignment with the associated notch  52 . The post  20  can then be moved inwardly and outwardly within the bore  24  until the desired height is reached. The actuator  42  is released and the crimp portion  48  is again in alignment with a different notch  52 . 
     Turning now to FIG. 5, the actuator or spring  40  is depicted as being provided with a saddle  28  that is located adjacent to the leading face  37  of the drawer  42  of the button subassembly  38 . A leaf spring member  50  extends from the saddle section within the socket  32  away from the open outside end of the socket  32 . A stop portion  90  extends from the other end of the saddle portion  48  in a direction away from the leading face  37  of the drawer  42 . In use, a distal end  92  of the leaf  50  contacts the stop portion  90  when the drawer  42  is pushed inwardly into the socket  32 . Thus, during many cycles of spring actuation, the risk of over-stressing the leaf  50  is minimized. 
     FIG. 7 depicts a rearward position of the actuator to which the actuator is biased, in which the saddle  48  engages a notch in the post after the button subassembly is released. FIG. 7 depicts the drawer in a forward position in which the saddle  48  is disengaged from any notch in the post. 
     It will readily be appreciated that the V-shaped notches  52  depicted in FIG. 4 may be deployed additionally or alternatively on the left-hand post. Correspondingly, the quadrilateral or square notch  94  can be provided additionally or alternatively on the right-hand post. 
     It should also be appreciated that the actuator or spring  40  (FIG. 5) could be oriented so that the leaf  50  could extend from either the right- or the left-side of the drawer  42  (FIGS.  6 - 7 ). Correspondingly, the stop  90  could easily be located on the left or on the right side of the drawer. 
     Thus, the actuator or spring  40  has two effective positions. In a first position, its purpose is to resist inward movement of the drawer  42  while removing the saddle  48  from a notch in the post. In a second position, the leaf  50  abuts the post  90 , which constrains the amount of deflection of the leaf  50  and thereby minimizes any tendency to become over-stressed when exposed to repeated cycles during operational use. 
     As depicted in FIG. 6, there is a gap  96  between the drawer  42  and the head  26 . Preferably, this gap  96  is enough to allow the crimped section to release from the post so that inward movement of the drawer  42  is limited. 
     Returning to FIG. 4, the square or quadrilateral securement notch  94  is positioned below the lowermost adjustment V-shaped notch  52 . Thus, when the headrest is displaced outwardly, so that the saddle  48  rides below the lowermost V-shaped notch  52 , the saddle  48  becomes firmly entrenched in the quadrilateral securement notch  94 . Once the saddle  48  is positioned within the quadrilateral securement notch  94 , a special tool is required for disengagement. In use, the special tool may deflect the outer surface of saddle  48  inwardly within the socket  32  from a flush-mount position before inward displacement. 
     It will readily be appreciated that the form of the head  26  can assume different aspects: round, oval, rectangular, square or combinations thereof. 
     If desired, a configuration such as depicted in FIG. 6 could be deployed on one side of the seatback  14  to engage one of a pair of posts extending from the head restraint pad  18 . If the other of the pair of posts is provided with a quadrilateral securement notch  94 , a form of button subassembly could be provided wherein the drawer  42  is flush-mounted in relation to the head  26 . When the saddle  48  engages the securement notch  94 , the drawer  42  will move outwardly to a flush position. Deliberate removal of that post from the seatback  14  will then only be accomplished by deploying a suitable tool. 
     Preferably, the spring  40  is made out of a spring steel. However, one skilled in the art could manufacture the spring out of other materials, such as other metals or polymers in the form of wire or bar stock. 
     Thus, it is apparent that there has been provided, in accordance with the invention, an improved head restraint assembly for motor vehicle seats that fully satisfies the objects, aims and advantages as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the following claims.