Abstract:
A seat assembly having headrest that includes an expansion assembly that operates to expand the cushion when the headrest is in the lower position. As the headrest is raised, the expansion assembly retracts, removing the bulge and creating a more planar surface for comfortably resting the head of a seat occupant. The headrest is also configured to reduce expansion of flatten as the seatback is folded flat.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This U.S. National Stage Patent Application claims priority to PCT Patent Application International Serial No. PCT/US2009/044946 filed on May 22, 2009, entitled “Seat Headrest” which claims priority to U.S. Provisional Application Ser. No. 61/055,523 filed on May 23, 2008, entitled “Expandable STO Headrest”, the entire disclosures of these applications being considered part of the disclosure of this application and hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention is generally directed to vehicle seats including headrests and more particularly rear seats having headrests commonly referred to as “shingle” style headrests, which include cushion bulges to incentivize an occupant to relocate the headrest to a proper height. 
         [0004]    2. Related Art 
         [0005]    Headrests are commonly used in motor vehicle seats to protect an occupant&#39;s head and neck from injury during a rear-end collision. To be effective, the headrest must be positioned a sufficient distance above the backrest of the seat relative to the seat occupant, as specified by applicable motor vehicle standards. 
         [0006]    In the case of unoccupied rear seat assemblies, a headrest raised to the normal “use” position will generally block a driver&#39;s rearward field of view, as depicted in  FIG. 1 . With traditional styles of headrest or restraint, the prior art has taught to completely remove headrests from the seat if unoccupied. However, this is cumbersome, the headrests are difficult to store when removed and the headrests must be reinstalled before an occupant occupies the seat. 
         [0007]    To address issues related to traditional headrests, the prior art has developed a headrest that is commonly called a “shingled” or shingle style head restraint as shown in  FIGS. 2 and 3 . The shingle head restraint is movable between raised (use) and lowered (non-use) positions. When in the lowered position, the headrest is configured to maximize the rear view for the operator of the vehicle by overlapping a substantial portion of the seatback. More specifically, when the seat is unoccupied, the shingled headrest can be pushed down, out of the driver&#39;s rearward field of view. Shingled headrests are also typically designed to be low profile in height in the lowered position, thereby not interfering substantially with the driver&#39;s view and minimizing the potential for interference with the seat in front when the seatback is folded down to a stowed position. 
         [0008]    The shingled headrest must be placed in a raised, normal use position, and is configured such that if there is a passenger in the rear seat, they would be incentivized when the headrest is in a lowered, non-use position to manually or intentionally adjust the headrest upward. For example, the bulge of the cushion, best illustrated in  FIG. 3 , when the seatback is upright and the headrest is in the lower position, pushes the seat occupant forward in the upper back area creating discomfort. 
         [0009]    The headrest should be movable to a lowered position so as not to unduly obstruct the rear view for a driver when the seat is unoccupied. While some headrests include motors and remote controls that allow drivers to flip the headrest, these are generally expensive and may interfere with the seat folding flat. In addition, if the headrest ever sticks in the flipped forward position, the seat is generally unusable. 
         [0010]    The headrest should also be designed in a manner to incentivize an occupant of the seat to raise or otherwise place the headrest in its normal use position when a person occupies the seat. One solution in the prior art seeks to configure the headrest with a fixed bulge that provides an uncomfortable bulge in the lower condition, thereby forcing an occupant to sit in discomfort until the headrest is placed in a proper use position for the seat occupant. While various strategies have been proposed, most have associated issues, such as exemplary illustrated in  FIG. 3 , where a bulging shingle-type headrest can create problems when the seatback is folded to a stowed position. More specifically, to make the lower portion comfortable for sitting, the bulging portion of the headrest contacts the seat cushion of the lower portion and may prevent the seatback portion from folding flat. 
         [0011]    Accordingly, there is a need for an improved headrest which is configured to minimize obstruction of a driver&#39;s rear view when the seat is unoccupied, which incentivizes an occupant to raise the headrest to a use position, and which still allows the seatback to fold flat. 
       SUMMARY OF THE INVENTION 
       [0012]    The invention is generally directed to vehicle seats including headrests and more particularly rear seats having headrests commonly referred to as “shingle” style headrests, which include cushion bulges to incentivize an occupant to relocate the headrest to a proper height. 
         [0013]    The headrest is coupled to the seat by at least one extension tube and includes an expansion assembly that operates to expand the cushion away from the extension tube when the headrest is in the lower position. As the headrest is raised, the expansion assembly retracts, removing the bulge and creating a more planar surface for comfortably resting the head of a seat occupant. The headrest is also configured to reduce expansion of flatten as the seatback is folded flat. More specifically, the expansion assembly is coupled to a cable that releases the applied force to the expansion assembly and thereby allows the expansion assembly to retract. 
         [0014]    The expansion assembly is generally formed from a skeletal structure, typically a linkage assembly. The expansion assembly generally includes a fixed member or link coupled to the extension tube. Extending from the fixed member is an intermediate link that is in turn coupled to a distal link. During expansion, the intermediate and distal link pivot relative to each other, as well as move relative to the fixed link, such that the intermediate link and distal link move from a position relatively aligned with the extension tube toward a position relatively perpendicular to the extension tube. The intermediate and distal links also move from a position that is closer to being aligned to a position that is closer to being perpendicular or even to an acute angle relative to each other. Of course, the intermediate and distal links do not need to reach the perpendicular position or even close to the perpendicular position to create the desired bulge. When the expansion assembly is relaxed, the intermediate and distal links move to a position more aligned with the extension tube and more aligned with each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a front view of an exemplary prior art seat and headrest; 
           [0016]      FIG. 2  is a front view of an exemplary prior seat and headrest with the headrest in a lowered position; 
           [0017]      FIG. 3  is a schematic sectional view illustrating the problems associated with folding a seat with a fixed STO headrest cushion; 
           [0018]      FIG. 4  is a rear perspective view of an exemplary seat in a vehicle; 
           [0019]      FIG. 5  is a front perspective view of an exemplary seat with the headrest in the lowered position; 
           [0020]      FIG. 6  is a front perspective view of an exemplary seat with the headrest in the raised position; 
           [0021]      FIG. 7  is a sectional view of the exemplary seat with the headrest in a lowered and expanded position; 
           [0022]      FIG. 8  is a schematic sectional view of the seat and headrest in the lowered and expanded position; 
           [0023]      FIG. 9  is a schematic sectional view of the seat and headrest in the raised and retracted position; 
           [0024]      FIG. 10  is a schematic view of the seat and headrest in an upright, intermediate and folded position; 
           [0025]      FIG. 11  is an enlarged sectional view of the headrest in a lowered and expanded position; 
           [0026]      FIG. 12  is a side view of the front seat (F) and rear seats showing position of the seat and headrest during folding, relative to the front seat; 
           [0027]      FIG. 13  is a schematic sectional view of the seat and headrest in the lowered and expanded position, and including a power assembly for raising and lowering the headrest; 
           [0028]      FIG. 14  is a perspective view of an exemplary seat in the folded position; 
           [0029]      FIG. 15  is a partial sectional view of the seat in  FIG. 14  along lines  15 - 15 ; and 
           [0030]      FIG. 16  is a schematic view of an exemplary seat and headrest in an exemplary expanded and lowered position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    As illustrated in the Figures, the present invention is directed to a seat assembly  30  for a vehicle  10 . As illustrated in  FIG. 4 , the seat assembly  30  is generally directed to rear seat assemblies or mid row seat assemblies. The seat assembly  30  generally includes a seat cushion  20  and a seat back  40  pivotally coupled together at a seat pivot axis  50 . A headrest  60  is coupled to the seat back  40  and generally includes an expansion assembly  80  that is configured to expand or flatten headrest  60  depending on the location of the headrest  60 , or the seatback  40  relative to the seat cushion  30 . 
         [0032]    The seat assembly  10  can take on a variety of designs, styles and configurations and the seat assembly  20  represented in the figures is only exemplary. The seat cushion  30  and seatback  40  generally include a seating surface  32  formed by a surface material that surrounds a cushion, as well known in the art. The seat assembly  20  is not directed to the front seats of vehicles but instead to seats behind the driver where the headrest  60  may obstruct the rear view of the driver if it isn&#39;t lowered during operation of the vehicle. 
         [0033]    The headrest  60  is generally styled or designed similar to many other shingled style headrests, but includes an expansion assembly  80  that allows the headrest to expand, or increase in width, and retract or decrease in width. The illustrated headrest is formed in an “L” shape with at least one extension rod or tube  70 , preferably two, extending from the inner side of the L-shape and in particular from the shorter leg of the L-shape. The headrest  60  includes a cushion portion  64  that is surrounded by a surface material forming an outer covering  62 . The outer covering  62  may be configured to stretch or flex, thereby allowing for easy expansion and retraction. The outer covering may be formed from two different surface materials, such as leather outer and sides with the inner side being formed from an elastic material that allows expansion while keeping the visible portions while the headrest is installed of the outer pulled tight to minimize wrinkles in the surface material. The extension rods  70  may be any style desired. 
         [0034]    The shingled-style headrest  60  is carried at the upper end  44  of the seatback  40  upon a mechanical structure which enables the headrest  60  to be raised from the position illustrated in  FIG. 5 , which is a non-use position, to the elevated use position, generally illustrated in  FIG. 6 . The seatback  40  may include a recessed portion  46 , as illustrated in the Figures to further improve the view of the driver by allowing the headrest  60  to be lowered approximately level with the upper edge  44  of the seatback  40 . A pull strap  160  can be fitted to mechanically and conveniently raise the headrest  60  to the use position. Therefore, an occupant seated in the assembly  20  can quickly extend the headrest  60  to its use position simply by pulling the strap  160  as noted. An appropriate linkage, actuated by the strap  48 , then forces the headrest  26  to an elevated position, such as that depicted in  FIG. 6 . 
         [0035]      FIGS. 8-9  are side views of the seat assembly  20  including the headrest  60  of the subject invention, wherein certain internal structures to the headrest  60  are shown in highly simplified, schematic form in particular the expansion assembly  80 . The headrest  60  and more particularly the expansion assembly  80  is shown including an internal, skeletal structure  88  comprising a fixed link  90  that is preferably, but not necessarily, rigidly connected to the extension tubes  70  that are telescopically mounted within the seatback  40 . Those of skill in the art will appreciate various alternative telescoping constructions other than extension tubes  70 , such as a single bar or other articulating configuration (not illustrated) may be used. In this example, however, the fixed link  90  is rigidly and immovably connected relative to the extension tubes  70  so that the fixed link  90  moves up and down with the extension tubes  70  as the headrest  60  is raised and lowered. 
         [0036]    The forward end of the fixed link  28  carries a first hinge  94  to which is pivotally connected an intermediate link  100 . The intermediate link  100  is pivotally connected to a distal link  110  via a second hinge  104 . Thus, the skeletal structure  88  of the headrest  60  includes a linkage assembly which is double-pivoted akin, somewhat, to a vehicular door hinge. These linkages and hinges are enveloped in a foam or other cushioning material  64 , which is surrounded by a trim covering or outer covering  62  which may be leather, vinyl, cloth or other flexible fabric-like material. A so called “A-surface” of the headrest  60  is indicated by the letter “A.” The A-surface directly contacts the back and/or head of a seated occupant. 
         [0037]    To operate the expansion assembly  80 , a push rod  130  or other appropriate device is disposed within the headrest  60  and acts between the fixed link  80  (or the extension tubes  70 ) and the intermediate link  100 , in a four-bar linkage arrangement. The push rod  130  is controlled by a cable  146  represented in  FIGS. 8 and 9  as a dashed line. When the cable  146  is pulled under tension, the push rod  130  is manipulated so as to displace the intermediate link  100  toward the A-surface of the headrest  60 , or away from the extension rods  70 . As perhaps best shown in  FIG. 11 , a tension spring  134  or other suitable device is operatively disposed between the intermediate link  100  and the distal link  110 . It is expected that the cable  146  will be coupled near the pivot axis  50 , to allow the pivoting of the seatback  40  to interact with the expansion assembly  80 , thereby expanding or flattening the headrest  60  depending upon the location of the headrest relative to the seat, as well as the location of the seatback  40  relative to the seat cushion  30 . 
         [0038]    When the headrest  60  is in its lower, non-use position and the backrest  40  is raised, such as shown in  FIGS. 8 and 11 , the cable  142  is automatically pulled so as to manipulate the pushrod  130  and thrust the intermediate link  100  in a forward direction, away from the extension tubes  70 . This, coupled with the action of spring  134 , causes the intermediate  100  and distal  110  links to flex forward and retract backward at the same time, thus bulging outwardly the A-surface of the headrest  60 , away from the extension tubes  70 . This outward bulging is designed to create discomfort in the back of a seated occupant, thereby incentivizing the occupant to move the headrest  60  to a raised, normal use position such as shown in  FIG. 9 . However, when the headrest  60  is raised into the use position, as shown in  FIG. 9 , tension on the cable  146  is relaxed, and the push rod  130  is then manipulated such that the pivoting links relax and allow the A-surface of the headrest  60  to take on more of a planar position, with the intermediate link  100  and distal link  110  moving to be increasingly parallel thereby creating a headrest that is more typical of prior art shingle-type headrest shapes. When the headrest  60  is returned to its lower position, as shown in  FIG. 11 , the linkages inside the headrest  60  flex forward in the manner described above, thereby creating a substantial bulge in the headrest bun. 
         [0039]    A mechanism box  150  illustrated in  FIGS. 9 and 11  schematically represents a device which may be controlled by a pull strap  160  ( FIG. 9 ) to conveniently raise the headrest  60  to its use position. Thus, an occupant simply pulls the strap  160 , and gears, pulleys, levers or other mechanical features contained within the box  150  thrust the extension tubes  70  upwardly and result in the contortions of the headrest  60  to create the flat shape as described above. Alternatively, the box  150  may be motorized in such a way to move the headrest  26  between its raised and lowered positions under the force of an electric motor, hydraulic actuator, pneumatic actuator or the like. 
         [0040]    Turning now to  FIG. 10 , the seatback  40  of the seat assembly  20  is shown articulated between use and storage or fold-flat positions, with a headrest  60  according to the subject invention superimposed in each of the possible positions relative to the position of the seatback  40 . With the seatback  40  in the upright position, as shown at the far right on  FIG. 10 , the headrest  60  is illustrated in both raised and lowered positions, with the internal linkage contorting the profile of the headrest bun when in the lowered position and the seatback  40  in the upright position to achieve the occupant discomfort described above. The cable  146  is shown schematically as a dashed line connected at its lowermost end to the pivoting feature of the seatback  40 . As the seatback  40  is folded to a storage position, the cable  146  is automatically manipulated to relax the internal linkage structure or expansion assembly  146 , thereby flattening the headrest  60  so that the bulged profile does not create an impediment to a flatly folded seatback  40 . Thus, as shown in  FIG. 15 , the headrest  60  enjoys all of the advantages of a typical prior art shingle-style headrest when the seatback  40  is folded flat, which includes enabling the seatback  40  to be tightly folded against the seat cushion  30 . 
         [0041]      FIG. 16  depicts yet another variation of this invention, wherein the first hinge  94  is rotated by the cable  146  and controls the distal link  110  with a modified push rod  130 . The expansion assembly further includes a roller  120 , such as a pulley or rod over which the cable  146  passes to a rotary lever  124 . The hinges  94 ,  104  may include clock springs (not shown) to provide a biasing force. Other features of this alternative design will become readily apparent to those of skill in the art upon examination of  FIG. 18 , together with its annotations. 
         [0042]    The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.