Abstract:
An extendible and retractable head rest system for a motor vehicle seat has a head rest coupled to a linkage and an actuator coupled to the linkage. The linkage includes an offset drive link that upon the actuator being actuated to extend the head rest system to an operative position, the linkage moves the head rest up and forward and upon the actuator being actuated to retract the head rest system to an inoperative position, the linkage moves the head rest back and down. In an aspect, the linkage kneels when the head rest reaches an upper position to move the head rest to a forward position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional Ser. No. 61/476,459, filed Apr. 18, 2011. 
     
    
     FIELD 
       [0002]    The present disclosure relates to head rest systems, and more particularly, to an automatically extendible and retractable head rest system for a rear vehicle seat. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    Rear vehicle seats have head rest systems that provide support for the heads of passengers seated in the rear vehicle seats. Such head rest systems have been manually extendible and retractable. More recently, such head rest systems have been automatically extendible and retractable, such as the head rest system disclosed in U.S. Pat. No. 7,145,263 for “Automatic Headrest Adjustment Control System for a Vehicle Seat Assembly.” In such automatic head rest systems, the head rest system is extended when a passenger is detected as seated in the vehicle seat and retracted when it is detected that the vehicle seat is vacant. 
         [0005]    One problem with automatic head rest systems is packaging them to fit in the back reset of the vehicle seat. It is therefore an object of the present disclosure to provide an automatic head rest system that is compact and more easily packaged in a back rest of a vehicle seat. 
       SUMMARY 
       [0006]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0007]    An extendible and retractable head rest system for a motor vehicle seat has a head rest coupled to a linkage and an actuator coupled to the linkage. The linkage includes an offset drive link that upon the actuator being actuated to extend the head rest system to an operative position, the linkage moves the head rest up and forward and upon the actuator being actuated to retract the head rest system to an inoperative position, the linkage moves the head rest back and down. In an aspect, the linkage kneels when the head rest reaches an upper position to move the head rest to a forward position. 
         [0008]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0009]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0010]      FIG. 1  is a side perspective view of an automatic head rest system in accordance with an aspect of the present disclosure in a retracted position; 
           [0011]      FIG. 2  is a side perspective view of the automatic head rest system of  FIG. 1  in an extended position; 
           [0012]      FIG. 3  is a side schematic view of the automatic head rest system of  FIGS. 1 and 2  showing a linkage of the automatic head rest system in a retracted position; 
           [0013]      FIG. 4  is a side schematic view of the automatic head rest system of  FIGS. 1 and 2  showing a linkage of the automatic head rest system in a partially extended position; 
           [0014]      FIG. 5  is a side schematic view of the automatic head rest system of  FIGS. 1 and 2  showing a linkage of the automatic head rest system in an extended position; 
           [0015]      FIG. 6  is an exploded assembly view of the automatic head rest system of  FIGS. 1 and 2 ; and 
           [0016]      FIG. 7  is a perspective view showing the automatic head rest system of  FIGS. 1 and 2  packaged in a back rest of a vehicle seat and in the extended position. 
       
    
    
       [0017]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0018]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0019]    With reference to  FIGS. 1-7 , an automatically extendible and retractable head rest system  100  in accordance with the above aspect of the present disclosure is described. Head rest system  100  includes a head rest  102  ( FIGS. 3 and 7 ), a top link  104 , a back link  106 , a front link  108 , an inner link  110 , a drive link  112 , a slider  114 , a drive rod  116 , a sleeve  118  ( FIGS. 2 and 7 ) and an actuator  120 . As shown in  FIG. 3 , head rest  102  is coupled to a front  122  of top link  104 . As best shown in  FIG. 6 , back link  106  includes opposed ends  124 ,  140 . End  124  of back link  106  is rotatably coupled to an upper back end  126  of top link  104 , such as by a pin  128  that is journaled in holes  130 ,  132  that extend transversely through the upper back end  126  of top link  104  and end  124  of back link  106 . In this regard, upper back end  126  of top link  104  in the illustrative embodiment has opposed ears  134  that project rearwardly on opposed sides  136 ,  138  of top link  104  at upper back end  126  which have opposed holes  130  therein. End  124  of back link  106  is received between opposed ears  134  and pin  128  inserted through holes  130  in ears  134  and hole  132  in end  124  of back link  106  to rotatably couple end  124  of back link  106  and upper back end  126  of top link together. 
         [0020]    As best shown in  FIG. 6 , end  140  of back link  106  is rotatably coupled to a rear, upper end  142  of slider  114 , such as by a pin  144  that is journaled in holes  146 ,  148  in upper end  142  of slider  114  and end  140  of back link  106 , respectively. In this regard, rear, upper end  142  of slider  114  in the illustrative embodiment has ears  150  that project upwardly from opposed sides  152 ,  154  of slider  114  which each has a hole  146  therein. End  140  of back link  106  is received between opposed ears  150  and pin  144  inserted through holes  146  in ears  150  and hole  148  in end  140  of back link  106  to rotatably couple end  140  of back link  106  and rear, upper end  142  of slider  114 . 
         [0021]    As shown in  FIG. 1 , a mid-section  155  of front link  108  is rotatably coupled to slider  114 . In this regard, as best shown in  FIG. 6 , front link  108  includes a narrower section  156 , a wider section  158 , and opposed ends  160 ,  162 , with opposed end  160  also an end of narrower section  156  and the other opposed end  162  also an end of wider section  158 . A hole  168  extends transversely through end  160  of front link  108  and a hole  170  extends transversely through end  162  of front link  108 . A hole  172  extends transversely through an end  174  of wider section  158  where it meets narrower section  156 . 
         [0022]    End  162  of front link  108  is rotatably coupled to top link  104  at generally a middle  176  of a bottom  178  of top link  104 . In the illustrative embodiment, top link  104  has opposed ears  179  extending downwardly with holes  180  (only one of which is shown) extending transversely therethrough. End  162  of front link  108  is received between ears  179  and a pin  182  is journaled in holes  180  in ears  179  and in hole  170  in end  162  to rotatably couple end  162  of front link  108  to the bottom  178  of top link  104  at generally the middle  176  thereof. It should be understood that the point where end  162  of front link  108  is rotatably coupled to the bottom  178  of top link  104  need not be in the exact middle of top link  104 , but can be offset from the exact middle in either direction and as shown in the illustrative embodiment, is rearward of the middle of top link  104 . 
         [0023]    Slider  114  is hollow, illustratively having a rectangular outer cross-section. An upper portion  184  illustratively has a rectangular inner-cross section and a lower portion  186  illustratively has a cylindrical inner-cross section having approximately the same inner diameter as an outer diameter of drive rod  116 , which is received in slider  114  for reciprocating movement therein as discussed in more detail below. 
         [0024]    An upper front portion  188  of slider  114  has an elongated vertical slot  190  ( FIGS. 1 ,  2  and  6 ) therein, illustratively an elongated U-shaped slot. Upper portion  184  of slider  114  is stepped, such that a top  192  of upper front portion  188  is lower than a top  194  of an upper back portion  196  forming a recess  198  thereat. 
         [0025]    Drive link  112  is attached to a top  200  of drive rod  116  with a forward offset end  202  of drive link  112  projecting into slot  190  in upper front portion  188  of slider  114  when drive rod  116  is received in slider  114 . Drive link  112  has an ear  204  projecting upwardly from the forward offset end  202  of drive link  112 . Ear  204  has a hole  206  extending transversely therethrough. 
         [0026]    Inner link  110  has ears  208 ,  210  projecting from opposed lower and upper ends  212 ,  214 , respectively. Each of ears  208 ,  212  has a hole  216  extending transversely therethrough. 
         [0027]    Opposed ends  212 ,  214  of inner link  110  are rotatably coupled to drive link  112  and to end  160  of front link  108 , respectively. Lower end  212  of inner link  110  is rotatably coupled to drive link  112  by a pin  218  that is journaled in hole  206  in ear  204  of drive link  112  and hole  216  in ear  208  of inner link  110 . Upper end  214  of inner link  110  is rotatably coupled to end  160  of front link  108  by a pin  220  that is journaled in hole  168  in end  160  of front link  108 . 
         [0028]    Front link  108  is received in elongated slot  190  in upper front portion  188  of slider  114  and rotatably coupled to slider  114  by a pin  222  that is journaled in hole  172  in front link  108  where the wider section  158  meets narrower section  156  and in holes  224  that extend transversely through upper front portion  188  of slider  114  adjacent top  192  thereof on opposed sides of elongated slot  190 . 
         [0029]    Slider  114  is received in sleeve  118  for reciprocal movement therein. Drive rod  116  is coupled to an actuator  120 , which may be a linear actuator, a driven lead screw, or other mechanism that provides motive force to drive rod  116  to reciprocate it in slider  114 , and thus reciprocate slider  114  in sleeve  118 . 
         [0030]    Top link  104 , back link  106 , front link  108 , inner link  110  and drive link  112  comprise a linkage  228  ( FIGS. 3-5 ) coupling head rest  102  to slider  114 . When head rest system  100  is in the retracted position, shown in  FIGS. 1 and 3 , front link  108  angles downwardly and rearwardly from top link  104  into slider  114  and inner link  110  angles upwardly and rearwardly from drive link  112  into slider  114  where upper end  214  of inner link  110  is rotatably coupled to end  160  of front link  108 . Drive link  112 , with front  202  and ear  204  disposed in elongated slot  190  in upper front portion  188  of slider  114  provides an off-set drive link that, in conjunction with the rest of linkage  228 , causes head rest  102  to “kneel” forward (such as by folding together) when it reaches it upper position as discussed below. 
         [0031]    Actuator  120  and sleeve  118  are disposed in a back rest  700  of a vehicle seat  702  ( FIG. 7 ). In operation, when head rest system  100  is deployed to its operative position such as when a passenger is seated in the vehicle seat, head rest  102  is moved upwardly and forwardly. Illustratively, head rest  102  is first moved to an upper position and then moved forwardly. Actuator  120  drives drive rod  116  to articulate upwardly in slider  114 , moving slider  114  upwardly. When slider  114  reaches the upper position (which is the upper position of head rest  102 ), drive rod  116  continues to move upwardly in slider  114  moving offset drive link  112  upwardly. This action of offset drive link  112  transmitted via inner link  110  to end  160  of front link  108  causes front link  108  to rotate about pin  222  journaled at the top  192  of upper front portion  188  of slider  114 , moving end  162  of front link  108  forward. This moves top link  104  forward moving head rest  102  to its forward position ( FIGS. 2 and 5 ). When head rest system is deployed to its inoperative position, such as when the vehicle seat is vacant, the above sequence is reversed. 
         [0032]    In an illustrative embodiment, head rest system  100  is automatically deployed to its operative position when a passenger is seated in the vehicle seat and the ignition switch turned on (if it is not already in its operative position. It is also automatically deployed to its retracted position when the ignition switch is turned on and the vehicle seat is vacant if it is not already in its retracted position. In this regard, an occupant sensor is included in the vehicle seat and used by a controller, such as the body controller of the vehicle, to determine whether to deploy the head restraint system to its operative or retracted position. 
         [0033]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.