Abstract:
A headrest support structure formed from multiple twisted energy-absorbing strands and strand bundles that greatly reduce the amount of energy rebounded into a vehicle occupant, especially when the vehicle in which the occupant is riding is hit from the rear (i.e., a rear end collision). In addition, headrest supports formed from twisted strand bundles, are ridged enough to completely support the headrest, but may be deformable enough to allow positional adjustment of the head rests in three dimensions. Currently, headrests are adjustable in only a single plane.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention pertains to headrests for motor vehicles and, more particularly, to adjustable, energy-absorbing headrests utilizing bundled strands or fibers as supports. 
       BACKGROUND OF THE INVENTION 
       [0002]    Typical vehicular headrests are supported by two rigid structural members, normally hollow metal rods. These metal rods are generally cylindrical and have diameters typically ranging between approximately 9 and approximately 12 millimeters. 
         [0003]    These metal rods are received in receiver tubes each having an inside diameter slightly larger than the diameter of the rod they must receive and retain. These receiver tubes are typically disposed within a vehicle seat back with tube-receiving openings in the top back portion of those seat backs. 
         [0004]    Structural detents along the outside vertical edge of at least one structural member is normally used in conjunction with a spring loaded catch, to set the elevation of the headrest into a position which better suits the comfort of the individual occupying the seat. This rigid metallic rod with receiver tube scheme has been in general automotive use for over 30 years. 
         [0005]    The existing structures and methods for providing headrest support and comfort adjustment typically have two problems: 
         [0006]    The first problem concerns the safety of the head, neck, and/or back of an occupant of the vehicle seat when the vehicle encounters a force imparted from the rear, for example, in a rear end collision. 
         [0007]    Referring first to  FIG. 1A , there is shown a side elevational, schematic view of a passenger  102  in a seat  112  including a headrest  108 , generally at reference number  100 . While a passenger  102  may keep his or her head  104  in contact with the front surface  106  of headrest  108 , other passengers may not. Regardless, when blunt force  110  is introduced from behind seat  112 , the mass of the passenger  102  is transferred into the back  114  of the seat  112  and headrest  108  as the seat  112 , typically attached to the frame of the vehicle, not shown, is propelled forward. This forward motion is represented by arrow  116 . 
         [0008]    As seat  112  with attached headrest  108  moves forward as shown by arrow  116 , front surface  106  of headrest  108  typically makes contact with the head  104  and back  118  of the passenger  102 . It will be recognized that when passenger  102  already has his or her head in contact with front surface  106  of headrest  108  when force  110  is applied to seat  112 , passenger  102  experiences increased resistance between his or her head  104  and headrest  108  as well as his or her back  118  and seatback  114 . 
         [0009]    While seatbacks  114  and headrests  108  are typically padded for comfort, the padding and padding support are generally designed to be self-restoring. This means that they revert to their original shapes and contours after being subjected to a compressing or other shape-distorting force, for example, force  110 . This restoration is sometimes accomplished with spring steel or other similar material, typically in the form of wire, neither shown, embedded within the seatback  112  and headrest  108 . Seatback  114  and headrest  108  are both typically formed from either closed cell or open cell foam padding, not specifically identified. Such foam materials also provide resistance. 
         [0010]    Consequently, when a force  110  is imparted to seat  112 , more specifically to seat back  114  and headrest  108 , seat back  114  and headrest  108  both rebound as they attempt to assume their original shape and contour, as well as their original position with respect to the vehicle frame. This rebounding process applies an opposite (relative to initial force  110 ) force  124 . Force  124  is also applied to and absorbed by passenger  102 . 
         [0011]    In addition to this rebound effect in the material composition, the seat frame, not shown, and structural members (e.g. supports  122 ) of headrest  108  offer additional rebound force. 
         [0012]    During introduction of force  110  from the rear direction, the change in position of vehicle and seat cause the seatback  114  and headrest  108  to move into contact with the individual&#39;s back  118  and head  104 , thus loading and transferring force presented by the mass of the body of occupant  102  into the vehicle seat  112 , headrest  108 , and structural members (e.g., supports  122 ). Very little of this energy is absorbed and dissipated. Rather, the energy is instead loaded into the seat padding, spring steel wire supports, headrest padding the spring steel wire support the seatback frame, the connecting member(s) between the seatback and seat bottom, and the headrest support members  122  between the seatback  114  and headrest  108 . 
         [0013]    In an existing headrest support design incorporating rigid structural supports, such supports typically having metallic content, the dynamic response of such structures to a rear impact may be seen in  FIG. 1B . Referring now also to  FIG. 1B , there is shown a side elevational, schematic view of the headrest  108  with a bottom plan schematic view  126  of the headrest support tube  122  shown therewith.  FIG. 1B  illustrates a common design utilizing a hollow metallic tube  122 . When a force  110  is applied to posterior side  130  of headrest support tube  122 , posterior side  130  compresses. As posterior side  130  compresses, anterior side  128  of headrest support tube  122  deforms, typically stretching. As the posterior side  130  and anterior side  128  of headrest support tube  122  return to their uncompressed/upstretched state (i.e., achieves equilibrium) “rebound” energy  124  is generated. Rebound energy  124  is then reintroduced into the seat  112  and seat occupant  102 . 
         [0014]    It would, therefore, be advantageous to provide a headrest support system that absorbs energy applied to it and reintroduces far less energy back into the seat&#39;s occupant than do existing headrest support systems. 
       DISCUSSION OF THE RELATED ART 
       [0015]    Several attempts to provide improved support systems for vehicle headrests may be found in the prior art. For example, U.S. Pat. No. 6,071,835 for LOAD LIMITING WEBBING issued Jun. 6, 2000 to Weimimg Tang, et al. teaches articles containing PET (Polyethylene terephthalate) fibers that absorb energy in a collision. [Column 1, lines 31-38] 
         [0016]    U.S. Pat. No. 7,588,289 for VEHICLE SEAT issued September 15, 2009 to Ola Boström, et al. discloses a vehicle seat comprising a squab and a backrest with an attached headrest. The headrest is provided with a mechanism that moves the headrest forwardly in the event that an impact should occur. A locking mechanism is provided to lock the headrest to prevent forward movement of the headrest in response to a predetermined signal. The signal may be generated in response to a rear impact in excess of a predetermined severity. 
         [0017]    Neither of these patents, taken singly, or in combination are seen to teach or suggest the Adjustable, Energy-Absorbing Headrest for Motor Vehicles or the like of the present invention. 
       SUMMARY OF THE INVENTION 
       [0018]    In accordance with the present invention there is provided a headrest support formed from energy-absorbing strands or fibers and bundles thereof that greatly reduce the amount of energy rebounded into a vehicle occupant, especially when the vehicle in which the occupant is riding is hit from the rear (i.e., a rear end collision). In addition, headrest supports formed from twisted strand bundles, are ridged enough to completely support the headrest, but may be deformable enough to allow positional adjustment of the head rests in three dimensions. Currently, headrests are adjustable in only a single plane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0020]      FIG. 1A  is a side elevational, partial, schematic view of a vehicle seat with a passenger seated therein in accordance with the prior art; 
           [0021]      FIG. 1B  is a side elevational, schematic view of the headrest portion of 
           [0022]      FIG. 1A  with a bottom plan schematic view of the support tube shown therewith; 
           [0023]      FIG. 2  is side elevational, schematic view of a single pair of intertwined strands; 
           [0024]      FIG. 3A  is a side perspective, schematic view of a cylindrical structure formed from a plurality of intertwined strand pairs of  FIG. 2 ; 
           [0025]      FIG. 3B  is a top or bottom plan, schematic view of the cylindrical structure of  FIG. 3A ; 
           [0026]      FIG. 3C  is a top or bottom plan, schematic view of the cylindrical structure of  FIG. 3B  showing heat conductive elements contained within the strand bundle; 
           [0027]      FIG. 3D  is a top or bottom plan, schematic view of the cylindrical structure of  FIG. 3B  showing an outer metallic layer thereon; 
           [0028]      FIG. 3E  is a side perspective, schematic view of an elongated structure having the cross section of  FIG. 3D  and suitable for forming a headrest support in accordance with the invention; 
           [0029]      FIG. 4A  is a side elevational, schematic view of a seat having a headrest supported on a support formed from twisted strand bundles; 
           [0030]      FIG. 4B  is an enlarged view of a portion of the seat and headrest of  FIG. 4A ; 
           [0031]      FIG. 4C  is a side elevational, schematic view of a seat having a headrest supported on a support formed from twisted strand bundles and formed so as to move the headrest to a passenger selected position; and 
           [0032]      FIG. 4D  is an enlarged view of a portion of the seat and headrest of  FIG. 4C . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0033]    The present invention provides new structures for supporting vehicular headrests that provide greater energy absorption capacity than support structures of the prior art. The novel structures minimize the secondary force on an occupant caused by restoration of support structures and materials after an impact, especially a rear end impact. In addition, the new support structures provide flexibility in adjusting headrest positions heretofore unknown. 
         [0034]    The present invention utilizes bundles of strands to implement headrest support structures. These strands are typically formed from a ductile metal such as an aluminum alloy. It will be recognized by those of skill in the art that various aluminum alloys or other ductile metals may be used to form strands or strand bundles suitable for forming headrest supports in accordance with the invention. It will be further recognized that fibrous or polymeric materials may also be used to form strands. Consequently, the invention is not considered limited to strands formed by any particular material. It will be further recognized that bundles of strands may contain strands formed from more than one material. 
         [0035]    Referring first to  FIG. 2 , there is shown a side perspective, schematic view of a pair of metal, fiber, or polymeric strands illustrating the conceptual foundation of the new energy-absorbing headrest support system  302  (best seen in  FIGS. 4A-4D ) of the invention, generally at reference number  200 . As used herein the term “metal strand or strands” is intended to include strands from any fibrous or polymeric material in addition to metal. 
         [0036]    A pair of strands  202   a,    202   b  is shown schematically in a twisted configuration. Such a configuration typically has two important properties: slip resistance, and rigidity. 
         [0037]    When strands such as  202   a,    202   b  in contact along a major axis  204 , have a substantially perpendicular force  206  imposed upon them, one strand (e.g., strand  202   a ) may move a slightly different distance than the other strand (e.g., strand  202   b ). Such movement results in strands  202   a,    202   b  rubbing or chafing against one another. Because strands  202   a,    202   b  are in contact with one another, the relative movement of strand  202   a  against strand  202   b,  etc. causes friction. This friction between strand  202   a  and strand  202   b  as they move relative to one another generates heat, and consequently, a small amount of the energy of force  206  is thereby absorbed. 
         [0038]    Force  206  might, for example, be generated by a rear end collision of a vehicle, not shown, having a headrest  108  supported by a strand based support structure  302  (best seen in  FIGS. 4A-4D ). 
         [0039]    By choosing the strand material and placement geometry, the amount of generated heat may be maximized and energy impinging on strands  202   a,    202   b  may be dissipated as it is converted to heat. In other words, the kinetic rebound energy is largely converted into heat that is then dissipated along the strands, strand bundles, or adjacent strands and/or strand bundles. 
         [0040]    Referring now also to  FIGS. 3A and 3B , there are shown side perspective, and top or bottom plan schematic views, respectively, of a multi-strand, elongated, quasi-cylindrical structure from which a support structure  302  for a vehicle headrest may be constructed, generally at reference number  220 . The single pair of strands  202   a ,  202   b  of  FIG. 2  illustrates the principle of operation of novel headrest support structure. A practical headrest support structure may be formed of multiple strands. The multiple strand pairs, triplets, quartets, etc.  202   a / 202   b,    202   c / 202   d,    202   e / 202   f,    202   g  . . .  202   n  of the multi-strand structure  220  merely multiply the structural ability to absorb energy. For simplicity, the term “pair” is used generically hereinafter to represent any multiple strand group wherein one or more strands  202   a,    202   c,    202   e,    202   g,  etc. may chafe against one another (e.g.,  202   b,    202   d,    202   f,    202   n,  etc.) to generate heat thereby absorbing energy. It will be recognized by those of skill in the art that strand bundles may be composed of homogenous or non-homogenous combinations of strand pairs, triplets, quartets, etc. and the invention in not considered to any particular combination of strand bundles. 
         [0041]    While structure  220  assumes that all strands  202   a,    202   b,  . . . ,  202   n  therein are identical, it will be recognized that alternate structures, none shown, may be constructed. Consequently, the invention is not considered limited to the strand structures chosen for purposes of disclosure. Rather, the invention is intended to include any strand configuration and combination of strand sizes, strand shapes, and strand materials. 
         [0042]    Referring now also to  FIG. 3C , there is shown a bottom plan, schematic view of the strand bundle  220  of  FIG. 3B  but with a plurality of added heat conducting components (e.g., strands)  210 , generally at reference number  230 . Heat conducting strands  210  may be formed from a heat conducting material such as copper, aluminum, or other good heat conducting metal. Alternately, any other suitable heat conducting material may be used. Strands  210  may be single strands placed among the strand pairs  202   a.    202   b,  etc., or alternately, heat conducting strands  210  may be entwined within selected strand pairs  202   a,    202   b,  etc., or heat conducting strands  210  may replace one of the non-heat conducting strands. 
         [0043]    Referring now also to  FIGS. 3D and 3E , there is shown a bottom plan, schematic view and a side perspective, schematic view of the strand bundle  230  of  FIG. 3C  with an outer metallic coating  208 , generally at reference number  240 . Metallic coating  208  protects strand bundle  230  and provides mechanical strength (e.g., rigidity) to strand bundle  230 , thereby forming a suitable component from which to form a headrest support member  302 , best seen in  FIGS. 4A and 4B . 
         [0044]    Metallic coating may be sprayed, plated, extruded, or otherwise deposited onto an outer surface of strand bundle  230  using materials and techniques or processes believed to be well known to those of skill in the art. Some alternate materials that may be used for such coatings or covers include, but are not limited to phenolic, rubber, plastic, or combinations thereof. Consequently, such material and techniques are not further discussed herein and the invention is intended to include any and all materials and or processes. 
         [0045]    Referring now also to  FIGS. 4A and 4B , there are shown a partial side elevational, schematic view and an enlarged portion thereof, respectively, of a vehicle seat using headrest support  302  formed from elongated structure  240 , generally at reference number  300 . 
         [0046]    In  FIGS. 4A and 4B , headrest support  302  is disposed in a substantially straight (i.e., unformed) configuration. Headrest support member  302  is both energy-absorbing and somewhat flexible. 
         [0047]    As previously discussed, elongated structure  240  when formed into a headrest support structure  302  may be formed by a seat occupant so as to position headrest  108  to a desirable position. 
         [0048]    Referring now also to  FIGS. 4C and 4D , the illustrations of  FIGS. 4A and 4B , respectively, show headrest support  302 ′ formed so as to move headrest  108  to a passenger selected position. 
         [0049]    Headrest support member  302  is both energy-absorbing and somewhat flexible. 
         [0050]    Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. 
         [0051]    Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.