Abstract:
A vehicle seat that is foldable can include a linkage mechanism for operatively withdrawing the headrest during fold down procedures and automatically extending the headrest to a use position during unfolding procedures of the seat.

Description:
BACKGROUND 
     1. Field 
     The disclosed subject matter relates to a self-raising headrest for a vehicle seat. More particularly, the disclosed subject matter relates to a headrest that self-raises in a fold-flat vehicle seat, whereby the headrest that is stowed against the seat upon folding of the seat returns to its extended position upon opening of the seat from the folded position to the unfolded position. 
     2. Brief Description of the Related Art 
     Passenger vehicles typically include a multitude of safety features to protect the occupants from harm during impact collisions. For example, seatbelts, airbags and active restraint systems have been employed in vehicles for many years. The safety features are designed to minimize the destructive forceful impact on the vehicle occupants that may be caused, for example, when a vehicle suffers a head-on collision, as well as providing protection when the vehicle is struck from behind in a rear-end collision. The amount and quality of such safety systems may vary among vehicle manufacturers, and most modern manufacturers also incorporate headrest restraints to protect the vehicle occupants in rear-end collisions. An effective headrest is one that is typically located directly behind the centerline of the occupant&#39;s head and is positioned no more than about two inches away from the head. 
     In a front-end collision, the vehicle&#39;s forward motion is abruptly stopped. The seat belts and airbags prevent the occupants from hurtling forward. The goal is to maintain the occupant in an upright position and to prevent his/her body from striking into hard surfaces, other occupants, or from being ejected out of the vehicle. 
     Conversely, in a rear-end collision, the impact forces are directed in the opposite direction. The vehicle is abruptly propelled forward, and the seated occupants are correspondingly thrown backward. Just as the seatbelt and/or airbag holds an occupant in the seat and restricts forward motion, a seatback and head restraint restricts rearward motion in a rear-end collision. 
     Importantly, the headrest should be positioned so that the occupant&#39;s head does not pivot over the headrest in a rearward direction. This pivoting action over the headrest could flex the upper spinal column. For example, an adjustable head restraint placed in a relatively lower position by a shorter person may not fit a subsequent, taller person whose head and upper spinal column can flex over the head restraint in a rear impact collision. 
     In U.S. Pat. No. 2,989,341, there is described a stationary reclining chair having a headrest that is extended to a pre-determined supporting position during the initial reclining movement of the chair. The reclining chair employs a combined guiding and actuating linkage in the form of a double arm actuating lever so that the pivotal mount moves in a prescribed arcuate path about the backrest pivot in response to the user&#39;s reclining movement. As the user sits in the upright chair and leans against the backrest, the corresponding force on the linkage engages the linkages and guiding mechanisms of the headrest to the extended position in order to support the back of the user&#39;s head. Further application of rearward force against the backrest of the chair causes the extended headrest and backrest to move as a single unit with no relative displacement between the backrest and headrest from the initial inclined position. Thus, the increase in angular relationship between the backrest and the chair seat does not change the relative position of the headrest in relation to the backrest in the further-reclined chair. 
     Also, PCT publication WO94/01302 provides a vehicle seat having a foldable backrest and a head restraint (i.e., headrest), where the headrest can be retracted into the backrest when folded down, and returned when the backrest is folded up. As the backrest is progressively folded down, a blocking device which normally maintains the backrest in an upright locked position is released, and a link arm pulls a yoke rod downwardly into the backrest, thereby retracting the headrest against the backrest. However, the device contains a significant limitation in that folding the vehicle seat upward returns the headrest to the “lowermost position of the adjustment range”, which must then be manually moved upward by hand to a higher adjustment position. 
     Further, U.S. Patent Publication No. US2002/0079723A1 discloses a mechanical actuating apparatus for a headrest mounted on a seat back which is able to be folded downward. The headrest is reportedly completely retracted from its pre-adjusted position and then restored to the original position when the seat back is folded upward. The traction device used is a Bowden cable, wherein the traction wire is connected to the headrest holder and allegedly counteracts the pulling force of an energy storing device which pulls the headrest into an extended position. The pivoting movement of the seatback is converted into a rolling-up or unrolling movement to extend or shorten a free length of the cable of the traction device. Unfortunately, the device is particularly limited by the use of such a Bowden cable traction mechanism, since the cable may slide out of position or become jammed. 
     Therefore, typical vehicle headrest restraints, including those described above, are deficient in their ability to provide a simple mechanism for a self-retracting headrest that minimizes clearance requirements for folding seatbacks. Moreover, a headrest restraint that returns to an extended position immediately upon unfolding of the backrest would be advantageous in providing greater safety for a user who can adequately adjust the headrest to match the user&#39;s head location as he/she sits in the vehicle seat, while simultaneously eliminating the situation where the user&#39;s head could pivot over the fully-retracted headrest during a vehicle collision. 
     SUMMARY 
     According to an aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end, and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position. 
     In accordance with another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage pushes directly on the headrest frame. 
     In accordance with yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage contacts a spring and said spring in turn contacts the headrest frame to raise the headrest to the extended position. 
     In accordance with still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described further comprising a spring means for storing or releasing energy from folding or unfolding of said foldable seat and wherein said spring is interposed between said linkage and said headrest frame. 
     In accordance with another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said lower channel is formed in a substantially linear configuration, and wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end, and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position. 
     In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage pushes directly on the headrest frame. 
     In yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage contacts a spring and said spring in turn contacts the headrest frame to raise the headrest to the extended position. 
     In another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described further comprising a spring means for storing or releasing energy from folding or unfolding of said foldable seat and wherein said spring is interposed between said linkage and said headrest frame. 
     In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said lower channel includes an angled configuration, and wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end; and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position. 
     In yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is automatically raised to a fully-extended position upon unfolding of said vehicle seat. 
     In another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is automatically lowered to a fully-retracted position upon folding of said vehicle seat. 
     In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is temporarily stalled and subsequently automatically raised to a fully-extended position upon unfolding of said vehicle seat. 
     Still other objects, features, and attendant advantages of the disclosed subject matter will become apparent to those skilled in the art from a reading of the following detailed description of embodiments constructed in accordance therewith, and taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given only by way of example, and with reference to the accompanying drawings, in which: 
         FIG. 1  is a side view of a folded down vehicle seat according to an embodiment of the disclosed subject matter; 
         FIG. 2  is a side view of the vehicle seat of  FIG. 1  in an unfolded state; 
         FIG. 3  is a magnified detail view of a self-raising headrest mechanism made in accordance with principles of the disclosed subject matter; 
         FIG. 4  is a magnified detail view of another self-raising headrest mechanism made in accordance with principles of the disclosed subject matter; and 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring to the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. 
     The foldable seat incorporating aspects according to the presently disclosed subject matter may be present in any portion of the vehicle including the vehicle front row, i.e., where the driver or passenger seat is situated. The foldable seat may also be incorporated into one or more seats located in the second row of the vehicle, which is the row directly located behind the front row driver&#39;s seat. Similarly, the foldable seat may comprise one or more seats located in the third or subsequent rows of the vehicle. Accordingly, the vehicle seat could be in a sedan, a sport utility vehicle, a van, a pickup truck, or any other type of vehicle that can incorporate one or more foldable seats. 
       FIG. 1  shows a foldable vehicle seat in the folded down position. The seat base  1  rests on the horizontal seat frame  2 , which is integrally fixed to the seat attachment rails  3 , 3 . The seat attachment rails  3 , 3  can be mounted onto the vehicle frame or floor structure (not shown) so that the entire foldable seat is securely attached to the vehicle. The seat  6  which a user sits on is movably attached to the backrest  4  at a second pivot axle  9 , whereby the second pivot axle  9  permits the seat  6  to travel horizontally to a limited degree toward the rear of the seat base  1  as the backrest  4  is rotated in direction B from a folded position (as in  FIG. 1 ) to an upright position (as shown in  FIG. 2 ). 
     In the folded position in  FIG. 1 , the backrest  4  has been rotated downward from an upright position by rotating the backrest  4  about the pivot wheel  7  and its associated first pivot axle  8 , in a counterclockwise direction (i.e., direction opposite to direction B). This pivot wheel  7  has a first pivot axle  8  which serves to rotatably connect the backrest  4  to the seat base  1 , while simultaneously allowing the backrest  4  to fold downward into a suitable position for stowing the foldable seat. The headrest  5  is shown in its fully retracted position as it nests partially or fully against the backrest  4 . This stowable position may also be referred to as the folded position. 
       FIG. 1  shows a support bracket  14  that includes pins  12  and  15  that are configured to ride in a lower channel  17  and an upper channel  18 , respectively. The relatively highest portion  13   b  of lower channel  17  shows the maximum height adjustment position of the second linkage pin  12 , and the highest portion  16   b  of the upper channel  18  similarly shows the maximum height adjustment position of the upper adjustment pin  15 . 
     The second linkage pin  12  is also connected to the linkage member  10 , and the first linkage pin  11  connects the linkage member  10  to the seat base  1 . As the backrest  4  is rotated in direction B, which corresponds to an unfolding or raising of the seat from the folded or stowed position, the lower end  4   a  of the backrest  4  pivots about the first pivot axle  8 , and the pivot wheel  7  rotates in a clockwise direction (direction B). Upon further rotation of the backrest  4  in direction B, the first linkage pin  11  restricts the linkage member  10  from any downward movement toward the seat frame  2 . Rather, the second linkage pin  12  is progressively driven within the lower channel  17  in a generally upward direction toward the highest portion  13   b  of the lower channel  17 . The upper adjustment pin  15 , which may be optionally present in the embodiment, is also driven in a generally upward direction toward the highest portion  16   b  of the upper channel  18 . The recliner support bracket  14  is correspondingly driven upward with the pins  12  and  15 , and the headrest  5  is thereby extended upward as the backrest  4  is unfolded. 
     The upper and lower channels,  18  and  17 , respectively, may each independently be a channel having smooth edges for infinite adjustments of the upper adjustment pin  15  and the second linkage pin  12  within the particular channel. Alternatively, either one or both of the channels ( 18 ,  17 ) may have ridges, contoured edges, or controlled stopping elements along the interior edges, whereby the headrest  5  may be adjusted to a level corresponding to the individual ridge points, contoured edges, or stopping elements. One or more of the upper and lower channels ( 18 ,  17 ) may have polished or lubricated edges, or may have linings of various materials to facilitate relatively smooth or constant movement of the second linkage pin  12  or upper adjustment pin  15  as it travels in the particular channel. In one embodiment, there may be a single channel at the upper or lower region of the recliner support bracket  14  only. However, a second or more additional channels can be provided for added direction and to provide positive stop limits for the headrest. 
     The linkage member  10  as shown is connected at its lower end via a first linkage pin  11  to the seat base  1 . The linkage member  10  is also connected at its upper end via a second linkage pin  12  to the recliner support bracket  14  for travel through the lower channel  17 . The second linkage pin  12  is adjustable and is able to travel within the confines of the lower channel  17  from the lowest portion  13   a  of the lower channel  17  to the highest portion  13   b  of the lower channel  17 . The channel can be provided in a separate linkage member or other portion of the seat structure. The degree of travel enables a user to adjust the headrest  5  to a desired vertical position to support the back of the user&#39;s head. 
     The action of folding down the backrest  4  in order to stow the entire foldable seat yields a sequence of events that is opposite the procedure described above. For example, as the backrest  4  is rotated downward, the pivot wheel  7  and first pivot axle  8  rotate in a counterclockwise direction. The linkage member  10  also rotates in a generally counterclockwise direction, causing the second linkage pin  12  to descend within the lower channel  17  toward the lowest portion  13   a  of the lower channel  17 . Similarly, the upper adjustment pin  15  is correspondingly drawn downward in the upper channel  18  toward the lowest portion  16   a  of the upper channel  18 . This action causes the headrest  5  to be retracted or drawn downward as the upper adjustment pin  15  and the second linkage pin  12  are both simultaneously drawn downward as well. In an embodiment where the optional upper adjustment pin  15  is not included, only the second linkage pin  12  travelling within the lower channel  17  operates to retract the headrest  5  as the backrest  4  is folded downward. Further rotation of the entire foldable seat toward the stowed position eventually causes the headrest  5  to be fully retracted into the stowable position. Thus, as shown in  FIG. 1 , the headrest  5  is stowed in its lowermost (or fully retracted) position in relation to the backrest  4 . 
     In  FIG. 2 , the foldable seat is shown in its unfolded or upright position. The headrest  5  has been extended in direction A to its maximum height. The backrest  4  and corresponding recliner support bracket  14  are also shown in their generally upright position. The second linkage pin  12  of linkage member  10  is shown in its uppermost adjustment position within the lower channel  17 , and the optional upper adjustment pin  15  is correspondingly shown in its uppermost adjustment position within upper channel  18 . The linkage member  10  connecting the recliner support bracket  14  to the headrest  5  is also shown in its most upright position relative to the backrest  4 . 
     In the folded seat position as shown in  FIG. 1 , the seatback has been rotated in a direction opposite to direction B, toward the seat  6 . The headrest  5  is shown in the fully retracted position. The upper pin  15  and the lower pin  12  both reside in their respective lowermost adjustable positions,  16   a  and  13   a , respectively, in the upper and lower channels  18  and  17 , respectively. The corresponding linkage member  10  is also shown in its lowermost adjustment position, due to the folded down position of the backrest  4 . 
       FIG. 3  shows an example of the straight lower channel  17   a . This straight lower channel  17   a  is configured for uniform movement of the first linkage pin  11  toward an upward direction without any great degree of horizontal movement of the first linkage pin  11 . In this exemplary configuration, as the seat is unfolded, there is a continuous proportional raising of the headrest (not shown) as the linkage member  10  and associated first linkage pin  11  drive the recliner support bracket  14  in an upward direction. In turn, the recliner support bracket  14  causes the headrest to be pushed upward. As the first linkage pin  11  reaches the highest portion  13   b  of the straight lower channel  17   a , then the recliner support bracket  14  will correspondingly drive the headrest to its maximum extended position. 
     As shown in  FIG. 4 , the seat can include structures that can provide a stall period during which the headrest is not driven upward during the initial unfolding of the seat. For example, the lower channel  17   b  may optionally be configured in an angled manner which provides a stall zone  17   c  as a portion of this angled lower channel  17   b . The stall zone feature operates such that the headrest does not raise during the initial stages of raising the seatback. This stalled or delayed raising of the headrest avoids, for example, the rear of any other interior vehicle seat located immediately in front of the foldable seat, or additional interior feature such as a console, until the seatback is unfolded (raised) to a point where the headrest would clear the obstruction. The “stall zone” is that portion of the angled lower channel corresponding to region  17   c  in  FIG. 4 . 
     As the foldable seat which has the incorporated stall zone  17   c  is raised, the first linkage pin  11  travels in a generally rearwardly direction within the angled lower channel  17   b . Once the first linkage pin  11  reaches the interior angle transition point  13   c  as shown in  FIG. 4 , the linkage member  10  continues to travel in a generally rearwardly direction, but gradually proceeds in a generally upward direction simultaneously within the angled lower channel  17   b . The angled lower channel  17   b  enables the first linkage pin  11  to travel rearwardly as the seat is unfolded, whereby the linkage member  10  also travels rearwardly to temporarily stall or delay the raising of the headrest. Upon unfolding of the seat, the linkage member  10  and associated first linkage pin  11  do not immediately push the recliner support bracket in an upward motion, but rather the linkage member  10  and associated first linkage pin  11  travel the distance of stall zone  17   c  from the lowest portion of the angled lower channel  17   b  until reaching the interior angle transition point  13   c  of the angled lower channel  17   b , wherein the first linkage pin  11  then begins to drive the recliner support bracket  14  in an upward direction and causes the headrest to be pushed upward. Once the first linkage pin  11  reaches the highest portion  13   b  of the angled lower channel  17   b , then the recliner support bracket  14  will in turn have driven the headrest to its fully extended position. 
     As indicated above, a seat that includes the above-described stall zone  17   c  may be applied in a second or third row foldable seat where the headrest raising is desirably stalled or temporarily delayed as the seat is unfolded. In the initial stages of unfolding the seat, the linkage member is initially driven generally rearwardly in the stall zone  17   c  as described. By temporarily delaying or “stalling” the raising of the headrest, interior obstructions may be cleared and the headrest then raises to its fully extended position as the seatback is further opened beyond the stall portion of the adjustment channel. As the seatback reaches the fully unfolded position, the headrest also reaches its maximum extended position. 
     The headrest can be adjusted to a specified position relative to the bracket  14  after the user has unfolded the seat through the use of typical adjustment mechanisms located between the headrest  5  and the linkage bracket  14 . 
     While certain embodiments of the disclosed subject matter are described above, it should be understood that the disclosed subject matter can be embodied and configured in many different ways without departing from the spirit and scope of the disclosed subject matter. For example, the interface between the linkage member and the recliner support bracket can be configured such that the components are at varying angles with respect to each other and include various connecting structures for connecting to the other vehicle seat components. Furthermore, the specific linkage as shown is not critical. Other various linkages can be used to provide similar kinetic motion to the seat, backrest and headrest. 
     The embodiments described above provide for direct movement of the headrest  5  via linkage bracket  14 . However, it is contemplated that the linkage bracket  14  could release a spring lock when the linkage bracket  14  is moved close to its upward most position. The spring lock would releases a spring that moves the headrest  5  outward by force of the spring. The headrest  5  could then be stowed back away by pushing it back down in the backrest  4  against the compressive force of the spring until the spring lock is again engaged. 
     Further, while the disclosed subject matter has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the disclosed subject matter. Each of the aforementioned documents is incorporated by reference herein in its entirety.