Abstract:
An articulated headrestraint system for a vehicle seat permits the user to adjust the headrest vertically, and to adjust the headrest either forwardly by using a pushbuttom mechanism, or rearwardly with respect to the top of the seat.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to an Articulated Head Restraint System that is part of an automobile. 
   BACKGROUND AND SUMMARY OF THE INVENTION 
   For a number of years the sole purpose of vehicle headrests was for the comfort of the occupant. The headrest could be adjusted up and down in most cases, and moved fore and aft in some expensive models. A typical headrest consists of a notched rod that may be straight or bent in a “U” shape and held in the car seat&#39;s guide tube. Foam and trim covers are placed on top of the rod (the headrest assembly) to give head and neck support and passenger comfort. The notches placed along the length of the rod help in moving the headrest assembly up and down, and locking the headrest in a specific place depending upon the occupant&#39;s height. 
   The headrests that move fore and aft are typically of a riveted design (4-way). The headrest is made in two parts. The upper section has welded brackets and a pair of notched rods. The rods are attached to the upper section with rivets and a friction pack comprising a wave washer, a flat washer and a rubber or plastic washer. The upper section pivots on the pair of rods at riveted joints. The upper section is foamed and trimmed for the headrest. The friction on the riveted joints control the movement of the upper section with respect to the lower notched rods. 
   The problem with existing designs is that efforts to move the headrest depend upon the dimensional tolerances of seat frame components. While 4-way headrests allow movement in both the up and down directions as well as fore and aft, they depend upon the friction on the rivet to keep in place and for movement. Increasing friction causes higher efforts, while reducing friction allows the upper section to fall since there is no locking mechanism. 
   With new regulations, headrests are becoming a part of the overall safety restraint system in the vehicles, and are being used as a protection device for whiplash in case of an accident. This requires the headrest to lock in a specific position and not move (at least in the aft direction) unless an activation device is used to move it from one position to another. 
   The present invention provides a head restraint system that overcomes some of the above-described problems of the related art. The invention allows the occupant to lock the headrest in a specific position. The headrest can be moved forward with minimal effort, while moving the headrest in the opposite direction requires a pushbutton activation. The invention also combines up and down motions and eliminates the effort issues related to seat frame dimensional tolerances. 
   The following prior art is related to this technology: U.S. Pat. Nos. 4,830,434 issued May 16, 1989 to Keiichi Ishida and Takami Terada for “Adjustable Headrest Device for Vehicle”; 5,669,668 issued Sep. 23, 1997 to Andrew Leuchtmann for “Folding Headrest in Particular for Motor Vehicles” and 6,045,181 issued Apr. 4, 2000 to Noriyuki Ikeda and Moriyuki Eguchi for “Adjustable Headres” 
   Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains, upon reference to the following drawings. 

   
     DESCRIPTION OF THE DRAWINGS 
     The description refers to the accompanying drawing s in which like reference characters refer to like parts throughout the several views and in which: 
       FIG. 1  is a font view of a vertically adjustable seat back illustrating the invention; 
       FIG. 2  is a view of the seat back of  FIG. 1  with the front cover removed; 
       FIG. 3  is a view of the seat back of  FIG. 1  with the rear cover removed; 
       FIG. 4  is a perspective view of the release button assembly; 
       FIG. 5  is another fragmentary view of the release button assembly in its rear position; 
       FIG. 6  is a view of the gear assembly in the disengaged position; 
       FIG. 7  is the view of the gear assembly with the seat back in the forward position; 
       FIG. 8  is a view of another preferred adjustable headrest with the front cover removed; 
       FIG. 9  is a view of the pushbutton assembly of  FIG. 8 ; 
       FIG. 10  is a top view of the assembly of  FIG. 9 ; 
       FIG. 11  is a sectional view as seen along lines  11 — 11  of  FIG. 9 ; 
       FIG. 12  is a view of the rivet assembly of the embodiment of  FIG. 9 ; 
       FIG. 13  is a fragmentary view of post  94 ; and 
       FIG. 14  illustrates another embodiment of the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings,  FIG. 1  illustrates an adjustable headrest  10  mounted on a vehicle seat back  12 , illustrated in phantom. Referring to  FIGS. 2 and 3 , headrest  10  includes a back cover  14  fastened to a front cover  16 . The two covers have edges formed together to form a hollow headrest housing. A U-shaped tubular upper support member  18  is captured between the front and rear covers in ridge means  20  and  22 , respectively. When the two covers are joined together, they combine to form a pair of lower slots  24  and  26 . The two covers also combine to form a side button opening  28 . Support member  18  is fixed to and moves with the two covers. 
   Support member  18  has a pair of parallel brackets  30  and  32 . The lower ends of the two brackets have rivet-receiving openings  34  and  36 , aligned along a pivotal axis  38 . 
   A pair of upright parallel legs  40  and  42  have upper flattened ends connected by rivet means  44  and  46  to the lower ends of brackets  32  and  30 , respectively. The headrest pivots about the upper end of legs  40  and  42  about axis  38 . 
   Referring to  FIG. 1 , legs  40  and  42  are received in sockets  48  and  50  in the seat back, locked against horizontal motion. The upper ends of legs  40  and  42  extend through slots  24  and  26  to permit the headrest to swing forwardly and rearwardly with respect to the seat back. 
   Referring to  FIGS. 4-7 , a gear segment  52  is integrally attached to the upper end of leg  40  and has, for illustrative purposes, six teeth  54  spaced in an arc about axis  38 . Pawl  56  is slidably mounted on bracket  32 . The pawl has a pair of teeth  58  engageable with teeth  54  on the gear segment. The pawl is slidable along the longitudinal axis of bracket  32  between a lower locking position, illustrated in  FIGS. 5 and 7 , in which teeth  58  engage teeth  54  to lock the headrest against rearward pivotal motion, and an upper release position, illustrated in  FIG. 6 , in which the pawl is separated from the gear segment teeth to permit the headrest to pivot rearwardly about the seat back. The gear segment teeth are so formed as to permit the pawl to ratchet around the gear segment when the headrest is moved forwardly, but to lock the pawl in engagement with the gear segment against rearward motion unless a pushbutton, to be described, is depressed. 
   Referring to  FIG. 4 , bracket  32  has an internal abutment  60 . A helical spring  62 , mounted between the upper end of the pawl and abutment  60 , biases the pawl towards its locking position with the gear segment. 
   The pawl has a cam surface  64  facing toward cam button opening  28 . A button housing  66  is tighty mounted in button opening  28 . Housing  66  is hollow and slidably supports a pushbutton  68  in an internal bore  70 , as shown in FIG.  16 . 
   The pushbutton has a pair of prongs  72  and  74  and a central tongue  76 . The tongue has a flat cam surface  78  which is slidably engaged with a complementary, flat cam surface  64  in a notch in the pawl. A return spring  80 , mounted in the button housing biases the pushbutton toward a locking position in which cam  78  slides on cam  64  so the pawl teeth  58  fully engage teeth  54  on the gear segment. By pushing the pushbutton toward bracket  32 , the pushbutton cam  78  will slide towards the pawl, biasing the pawl upwardly away from the gear segment, towards the release position, illustrated in FIG.  6 . 
   In operation, the user readjusts the headrest by either pushing the headrest forwardly, or by pushing the pushbutton to release the pawl from the gear segment to swing the headrest toward a rearward position, and then releases the pushbutton to lock the headrest in its adjusted position. 
     FIGS. 8-11  show another embodiment of the invention in which headrest  90  is vertically adjustable on a pair of posts  92  and  94  that extend above the top of the vehicle seat back. Outer covers  14  and  16  are removed for clarity. This design allows vertical adjustment of the headrest on posts  92  and  94 . This design also allows the headrest to pivot as well as move vertically on posts  92  and  94 . 
   Post  92  has a series of vertically and evenly spaced notches  96 . A pair of support blocks  98  and  100  have through holes  102  and  104  slidably mounted on posts  92  and  94  for up and down motion. 
   A U-shaped support member  106 , has a pair of legs  108  and  110  pivotally mounted on support blocks  98  and  100 . Pivot brackets  114  and  115  are welded to the lower ends of support legs  108  and  110 , respectively. Each bracket is mounted in a slot in its respective support block. The lower end of the two support brackets are pivotally mounted on their respective support blocks by rivets  117   a  and  117   b.    
     FIGS. 9 and 10  show a button housing  118  mounted on the hollow headrest housing, not shown. A pushbutton  120  is slidably mounted in the button housing so as to be moveable either toward or away from bracket  114 . The pushbutton has a frusto-conical cam surface  124 , which slidably engages a complementary cam surface  126 , carried on pawl  128 . Pawl  128 , is vertically slidably mounted on bracket  114 , and has locking teeth means  130 , for engaging teeth  132 , of a gear segment  134 , FIG.  11 . Pushing button  120  separates the pawl from the gear segment to permit the headrest to pivot about rivet  116 . 
   Referring to  FIGS. 9 and 10 , the pushbutton cam surface  124  engages a vertical adjustment detent  136 . When the pushbutton is depressed toward the right as viewed in  FIG. 10 , the detent pivots counter-clockwise, about pin  137  so that a tooth  137   a  disengages a vertical adjustment notch  96  on post  92 . A leaf spring  138 , held in the headrest housing, not shown, keeps constant pressure urging the detent toward post  92  so that when pushbutton  120  is released, the detent can snap into a notch  96  on bar  92 . 
     FIGS. 12 and 13  show a view of support block  100 , which has lateral movement in hole  104 . Post  94 , has two grooves  94 A and  94 B for retention in block  100 , along with a spring  99 , which maintains a constant pressure on block  100 , in the event that there is any centerline variation in the seat back assembly. 
     FIG. 14  shows another embodiment of the design to accommodate any variation of the centerline in the seatback assembly. Support block  150  has a bore  152  which receives post  94 . Bore  152  has a larger diameter than the post so block  150  is laterally movable on the post. Ball  154 , has a hole  156  that has a slip fit to post  94 . Block  150  has a lateral hole  158  which receives ball  154  so that the post is able to move laterally and angularly in block  150 . A spring  160  placed between ball  154 , and a rivet  162  in bore hole  158  keeps constant pressure of the ball on post  94 . Post  94  has a groove  162  for receiving a locking clip, not shown, to hold post  94  in the headrest. 
   The safety features of this design are such that the headrest will lock in the set position and will not rotate or pivot back away from the driver&#39;s head, or drop lower down into the seat unless the pushbutton is depressed.