Abstract:
A portable, compact folding furniture piece ( 10 ) constructed as a seat or table is configured for convenient storage. The folding furniture piece comprises an object support assembly ( 24 ) that is configured for operative connection to a mounting structure ( 12 ) and includes a spring mechanism ( 40, 42 ) securing together as a flexible unit a support mount ( 36 ), an articulated vertebral column ( 26 ), and a support base ( 38 ). The spring mechanism exhibits flexibility properties such that the object support assembly assumes at rest an unfolded state and, in response to an externally applied bending force, assumes a folded state. In the unfolded state, the vertebral column is substantially straight to provide a closed support surface ( 44 ). In the folded state, the vertebral column is curved to provide a raised, open support surface on which an object can rest. Depending on the embodiment of the furniture piece, the object can be a person or thing.

Description:
RELATED APPLICATION 
     This application claims benefit of U.S. Provisional Patent Application No. 61/345,854, filed May 18, 2010. 
    
    
     COPYRIGHT NOTICE 
     ©2011 Aria Enterprises, Inc. A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR §1.71(d). 
     TECHNICAL FIELD 
     This disclosure relates to furniture pieces and, in particular, to folding seats and tables each constructed with an articulated vertebral column that facilitates compact, convenient seat or table surface storage. 
     SUMMARY OF THE DISCLOSURE 
     A portable, compact folding furniture piece constructed as a seat or table is configured for convenient storage. The folding furniture piece comprises an object support assembly configured for operative connection to a mounting structure. The object support assembly includes an articulated vertebral column positioned between a support mount and a support base and a spring mechanism securing together as a flexible unit the support mount, vertebral column, and support base. The vertebral column includes multiple vertebral members. The spring mechanism exhibits flexibility properties such that the object support assembly assumes at rest an unfolded state and, in response to an externally applied bending force, assumes a folded state. In the unfolded state, the vertebral column is substantially straight to provide a closed support surface. In the folded state, the vertebral column is curved to provide a raised, open support surface on which an object can rest. Depending on the embodiment of the furniture piece, the object can be a person or thing. 
     Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are isometric views of a portable, compact folding seat, shown in, respectively, an unfolded state and a folded state, according to one embodiment. 
         FIGS. 3 ,  4 , and  5  are, respectively, top plan, side elevation, and bottom plan views of the folding seat in the unfolded state shown in  FIG. 1 . 
         FIG. 6  is an exploded view of the folding seat shown in  FIG. 1 . 
         FIGS. 7A and 7B  show the construction and operation of a seat assembly in, respectively, the unfolded state of  FIG. 1  and the folded state of  FIG. 2 . 
         FIGS. 8A ,  8 B, and  8 C show, respectively, side elevation, top plan, and end views of a beveled vertebral slat for use in the seat assembly. 
         FIGS. 9A and 9B  show, in its respective unfolded and folded states, the folding seat installed in a stadium or theater seating arrangement in which seats are installed on a stepped floor surface. 
         FIG. 9C  shows the folding seat in its unfolded state of  FIG. 9A  and including a mounting member hinge-mounted to the seat back. 
         FIGS. 10A and 10B  are isometric views of the folding seat of  FIGS. 1 and 2 , configured in an alternative embodiment as a freestanding chair shown in, respectively, an unfolded state and a folded state. 
         FIGS. 11A and 11B  are side elevation views of the freestanding chair of  FIGS. 10A and 10B , respectively. 
         FIG. 12  is an exploded view of the freestanding chair of  FIGS. 10A and 10B , showing modifications of a seat back foam layer and a seat assembly foam layer of the folding seat for accommodating chair leg sets to thereby form the freestanding chair. 
         FIG. 13  is a perspective view of the frontal portions of two side-by-side wall-mounted folding seats, the left-side seat shown in a folded state and the right-side seat shown in an unfolded state. 
         FIGS. 14A and 14B  are side elevation views of the wall-mounted folding seat of  FIG. 13  shown in, respectively, its unfolded state and its folded state. 
         FIG. 15  is a perspective view of the frontal portions of two side-by-side floor-mounted folding seats, the left-side seat shown in a folded state and the right-side seat shown in an unfolded state. 
         FIG. 16  is a perspective view of the frontal portions of two side-by-side wall-mounted folding tables, the left-side table shown in a folded state and the right-side table shown in an unfolded state. 
         FIGS. 17A and 17B  are side elevation views of one wall-mounted folding table of  FIG. 16  shown in, respectively, its unfolded state and its folded state. 
         FIGS. 18A and 18B  and  FIGS. 19A and 19B  are pairs of isometric and end views showing a first alternative embodiment of a vertebral column in, respectively, a straightened, relaxed configuration corresponding to an unfolded state of a folding seat, and in a curved configuration corresponding to the folded state of a folding seat. 
         FIGS. 20A and 20B  are respective isometric and end views showing one interior vertebral link of the first alternative embodiment of the vertebral column. 
         FIGS. 21A and 21B  and  FIGS. 22A and 22B  are pairs of enlarged fragmentary respective isometric and end views showing in detail the interconnection of multiple vertebral links of the first alternative embodiment of the vertebral column in, respectively, the straightened configuration of  FIGS. 18A and 18B , and in the curved configuration of  FIGS. 19A and 19B . 
         FIGS. 23A and 23B  and  FIGS. 24A and 24B  are pairs of isometric and end views showing a second alternative embodiment of a vertebral column in, respectively, a straightened, relaxed configuration corresponding to an unfolded state of a folding seat, and in a curved configuration corresponding to a folded state of a folding seat. 
         FIGS. 25A and 25B  are respective isometric and end views showing one interior vertebral link of the second alternative embodiment of the vertebral column. 
         FIGS. 26A and 26B  and  FIGS. 27A and 27B  are pairs of enlarged fragmentary respective isometric and end views showing in detail the interconnection of multiple vertebral links of the second alternative embodiment of the vertebral column in, respectively, the straightened configuration of  FIGS. 23A and 23B , and in the curved configuration of  FIGS. 24A and 24B . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 and 2  are isometric views of a portable, compact folding seat  10 , in a preferred embodiment shown in, respectively, an unfolded state and a folded state.  FIGS. 3 ,  4 , and  5  are, respectively, top plan, side elevation, and bottom plan views of folding seat  10  in the unfolded state shown in  FIG. 1 . 
     With reference to  FIGS. 1-5 , folding seat  10  comprises a generally rectangular seat back  12  that has a seat back rest surface  14 , a seat back mount surface  16 , a top end  18 , and a bottom end  20 . A first or seat back foam layer  22  is bonded with adhesive or Velcro™ fabric hook and loop fastener material to, and covers the surface area of, seat back rest surface  14  to provide a padded seat back  12 . A seat assembly  24  is positioned on seat back foam layer  22  and secured to seat back  12  near its bottom end  20 . Seat assembly  24  is of shorter length than that of seat back  12 . Seat assembly  24  includes a vertebral column  26  of nine lengthwise parallel-aligned beveled vertebral members or slats  28   b  and corner vertebral members or slats  28   c  of equal lengths positioned between a seat mount  36  and a seat base  38 . Beveled vertebral slats  28   b  have beveled ends  30   b , and corner vertebral slats  28   c  have right-angle corner ends  30   c . Vertebral column  26  is formed with a beveled vertebral slat  28   b  at each end. Between the ends of vertebral column  26  is an alternating sequence of beveled vertebral slats  28   b  and corner vertebral slats  28   c  such that each corner vertebral slat  28   c  is positioned between two beveled vertebral slats  28   b.    
       FIG. 6  is an exploded view of folding seat  10 ;  FIGS. 7A and 7B  show the construction and operation of seat assembly  24  in, respectively, the unfolded state of  FIG. 1  and the folded state of  FIG. 2 ; and  FIGS. 8A ,  8 B, and  8 C show several views of beveled vertebral slat  28   b  marked with preferred dimensions. With reference to  FIGS. 1 ,  2 ,  6 ,  7 A,  7 B,  8 A,  8 B, and  8 C, first and second spaced-apart spring bands  40  and  42  secure together, as a flexible unit, seat mount  36 , vertebral column  26 , and seat base  38 , the last of which having a seat surface  44 . A second or seat assembly foam layer  46  covers the surface area of seat assembly  24  and forms an interface layer between seat assembly  24  and seat back foam layer  22 . Seat assembly foam layer  46  is bonded with adhesive or Velcro™ fabric hook and loop fastener material to seat base  38 , and the portion of seat assembly foam layer  46  covering seat surface  44  provides a padded seat for an occupant. Seat assembly  24  is secured to seat back  12  by four bolts  50  (only one shown) passing through axially aligned holes  52  in seat mount  36 , spacer blocks  54  set in aligned rectangular openings  56  in seat assembly foam layer  46  and seat back foam layer  22  ( FIG. 6 ), and seat back  12  in the manner described below with reference to  FIG. 6 . 
     With particular reference to  FIG. 6 , folding seat  10  is assembled by first joining the component parts of seat assembly  24 . This is accomplished by placing vertebral slats  28   b  and  28   c  alternately in lengthwise parallel alignment with their ends set even with one another to define for vertebral column  26  linear, discontinuous side margins along its length. Each of spring bands  40  and  42  has nine sets of two spaced-apart holes  60  that are located to receive screws  62  ( FIGS. 7A and 7B ) to hold vertebral slats  28   b  and  28   c  in the alignment configuration described above. Each of spring bands  40  and  42  has multiple sets of holes  64  through which screws  66  ( FIGS. 7A and 7B ) pass to secure the ends of spring bands  40  and  42  to seat mount  36  and seat base  38  to form seat assembly  24  as a flexible unit. The cross-sectional area of each of vertebral slats  28   b  and  28   c  defines a trapezoidal-shaped perimeter having nonparallel opposite sides of equal lengths. Each of the nonparallel sides is inclined at an 85.5° angle  70  ( FIG. 8C ) relative to the base of the trapezoid. Inclination angle  70  is set in cooperation with a 10° cant angle  72  ( FIGS. 9A and 9B ) of seat back  12  to establish a desired substantially horizontal, raised seat surface  44  for a seat occupant when folding seat  10  is in its folded state. 
       FIGS. 8A ,  8 B, and  8 C show beveled vertebral slat  28   b  marked with preferred dimensions (in millimeters) and formed with beveled ends  30   b.  Corner vertebral slats  28   c  are of the same dimensions as those of beveled vertebral slats  28   b , except that corner ends  30   c  form right angles relative to the base of the trapezoid. The alternating sequence of beveled slats  28  and corner slats  28   c  in vertebral column  26  prevents pinching of the seat occupant&#39;s fingers while folding seat  10  relaxes to its unfolded state. 
     With particular reference again to  FIG. 6 , four rectangular openings  56  of each of seat back foam layer  22  and seat assembly foam layer  46  are arranged in a rectangular pattern to receive corresponding rectangular spacer blocks  54  of the same height as the combined thicknesses of seat back foam layer  22  and seat assembly foam layer  46 . Four bolts  50  pass through holes  52  in seat mount  36 , spacer blocks  54 , and seat back  12  to complete the assembly of folding seat  10 . Two spaced-apart rubber feet  74  are inserted in the bottom end of seat mount  36  to prevent excessive wear of folding seat  10  when it is dragged across the surface of a floor during transportation to and from storage. 
       FIGS. 9A and 9B  show, in its respective unfolded and folded states, folding seat  10  installed in a stadium or theater seating arrangement in which seats are installed on a stepped floor surface  90 . A floor-contacting end  92  of folding seat  10  rests on a floor portion  94 , and seat back mount surface  16  of seat back  12  is mounted to a riser  96 . Skilled persons will appreciate that folding seat  10  can be installed in other tiered seating arrangements, such as, for example, in bleacher structures or on sloped floor surfaces. 
     With reference to  FIGS. 4 ,  5 ,  9 A,  9 B, and  9 C, a mounting member  100  extends at a 10° angle  72  relative to seat back mount surface  16  to mount folding seat  10  to riser  96  with seat back  12  inclined at a 10° cant angle. Mounting member  100  is preferably set at a fixed 10° angle  72 .  FIG. 9C  shows a higher cost mounting alternative, in which mounting member  100  is hinge mounted to seat back  12  to permit mounting member  100  to pivot outwardly from a flush mount storage position in a recess (not shown) in seat back mount surface  16  to a 10° angle  72  operating position. Mounting member  100  has an L-shaped slot  102  with its longer segment  104  and its shorter segment  106  oriented, respectively, perpendicular and parallel to bottom end  20  of seat back  12 . Folding seat  10  can be dropped downwardly toward floor portion  94  such that longer segment  104  of slot  102  receives a mounting screw  108  anchored in riser  96  and then moved horizontally along shorter segment  106  of slot  102  to releasably lock folding seat  10  in place.  FIG. 2  shows in seat back foam layer  22  and seat back  12  an access hole  112  through which a screwdriver can be inserted to turn mounting screw  108  passing through mounting member  100  and into riser  96 .  FIG. 5  shows that longer segment  104  is offset from and the distal end of shorter segment  106  is aligned with a longitudinal center line  110  of seat back  12  so that, when folding seat  10  is locked in place, mounting screw  108  is positioned along center line  110 .  FIG. 4  shows folding seat  10  with floor-contacting end  92  inclined at a 10° bevel angle  114 . Bevel angle  114  matches the 10° cant angle of seat back  12  and thereby causes folding seat  10 , when installed, to rest level on floor portion  94 .  FIG. 9B  shows folding seat  10 , when installed and in its folded state, with a substantially horizontal, raised seat surface  44  on which a seat occupant can sit. 
     With particular reference to  FIG. 6 ,  FIGS. 7A and 7B , and  FIGS. 9A and 9B , whenever no external force is applied to seat base  38  of seat assembly  24 , spring bands  40  and  42  cause folding seat  10  to automatically assume at rest its unfolded state ( FIGS. 7A and 9A ), in which vertebral column  26  is substantially straight.  FIG. 6  shows small magnets  116  set in recesses  118  in seat surface  44  and in seat back rest surface  14  of seat base  38  and seat back  12 , respectively. Magnets  116  ensure that seat assembly  24  snaps shut and remains closed, i.e., seat mount  36  and seat base  38  lie in substantially the same plane, when folding seat  10  is unoccupied. Whenever a seat occupant pulls seat base  38  completely away from seat back  12  to present a raised, substantially horizontal sitting surface, folding seat  10  assumes its folded state ( FIGS. 7B and 9B ), in which vertebral column  26  is curved. Opening folding seat  10  applies to vertebral column  26  a bending force that closes the spaces between adjacent nonparallel sides of vertebral slats  28   b  and  28   c  and thereby squeezes adjacent vertebral slats  28   b  and  28   c  together to form a curved vertebral column  26 . The weight of an occupant sitting on foam padded seat base  38  maintains the folded state of folding seat  10  as it supports the seat occupant. 
     Preferred materials used in the construction of folding seat  10  include 13-ply baltic birch plywood for seat back  12 , vertebral slats  28   b  and  28   c , seat mount  36 , and seat mount  38 ; spring steel for spring bands  40  and  42 ; and urethane foam material for seat back foam layer  22  and seat assembly foam layer  46 . 
       FIGS. 10A and 10B  are isometric views of folding seat  10 , configured in an alternative embodiment as a freestanding chair  120  shown in, respectively, an unfolded state and a folded state.  FIGS. 11A and 11B  are side elevation views of freestanding chair  120  in, respectively, its unfolded state and its folded state.  FIG. 12  is an exploded view of freestanding chair  120 , showing the addition of two similar chair leg sets  122  to and modifications of seat back foam layer  22  and seat assembly foam layer  46  of folding seat  10  to accommodate chair leg sets  122  and thereby form freestanding chair  120 . 
     With reference to  FIGS. 10A ,  10 B,  11 A,  11 B, and  12 , the component parts of folding seat  10  and freestanding chair  120  are the same, except for substitution of chair leg sets  122  for spacer blocks  54  and substitution of two slots  124  for different pairs of rectangular openings  56 . With particular reference to  FIG. 12 , each of chair leg sets  122  has an upright portion  130  extending from and positioned at an 80° angle  132  relative to a floor support portion  134 . Upright portion  130  has the same height and width as the height and width of spacer blocks  54  and includes two holes  52  positioned so that bolts  50  pass through them during assembly of the chair. Rectangular openings  56  in seat back foam layer  22  and seat assembly foam layer  46  are replaced by slots  124  that extend into foam layers  22  and  46  from their respective bottom ends and cover a distance equal to the length of upright portions  130 . Upright portions  130  fit into slots  124 , and bolts  50  passing through holes  52  secure chair leg sets  122  in place to form freestanding chair  120 . 
       FIG. 13  is a perspective view of the frontal portions of two side-by-side wall-mounted folding seats  150 , one of which (left side) shown in a folded state and the other of which (right side) shown in an unfolded state.  FIGS. 14A and 14B  are side elevation views of wall-mounted folding seat  150  in, respectively, its unfolded state and its folded state. With reference to  FIGS. 13 ,  14 A, and  14 B, the component parts of folding seat  10  and wall-mounted folding seat  150  are the same, except for substitution of an inclined wall surface  152  as a common seat back of one or a row of multiple folding seats for a separate seat back  12 . Wall surface  152  is inclined at an 80° angle  154  relative to a floor  156 . Wall-mounted folding seat  150  is useful for installation in public transportation vehicles (e.g., subway car) or any other application in which compact, flat seat storage would be of benefit. When wall-mounted folding seat  150  is installed, seat back foam layer  22  rests against wall “I” surface  152 . Bolts  50  pass through holes  52  drilled at predetermined locations in wall surface  152 , as shown in  FIG. 13 . 
       FIG. 15  is a perspective view of the frontal portions of two side-by-side floor-mounted folding seats  10 , one of which (left side) shown in a folded state and the other of which (right side) shown in an unfolded state. With reference to  FIG. 15 , folding seats  10  are inclined at a 10° cant angle  72  in similar manner to that shown in  FIGS. 9A and 9B  and fastened to an inverted U-shaped railing  160  that is anchored to a floor  162 . Each of floor-mounted seats  10  can be secured to railing  160  by passing mounting screw  108  through mounting member  100  and a threaded hole (not shown) provided in the horizontal section of railing  160 . 
       FIG. 16  is a perspective view of the frontal portions of two side-by-side wall-mounted folding tables  170 , one of which (left side) shown in a folded state and the other of which (right side) shown in an unfolded state.  FIGS. 17A and 17B  are side elevation views of one wall-mounted folding table  170  in, respectively, its unfolded state and its folded state. With reference to  FIGS. 16 ,  17 A, and  17 B, the component parts of wall-mounted folding seat  150  and wall-mounted folding table  170  are the same, except for substitution of a flexible, uncushioned table (i.e., hard table top) surface layer  46 ′ for seat assembly foam layer  46  and a wall surface  172  as a mounting surface of folding table  170  for a separate seat back  12  and its corresponding seat back foam layer  22 . Wall surface  172  is oriented at a 90° angle relative to floor  156 , in a conventional arrangement. Wall-mounted folding table  170  is useful for installation in an office furniture system (e.g., a work space cubicle divider wall) or any other application in which compact, flat table storage would be of benefit. When wall-mounted folding table  170  is installed, table surface layer  46 ′ rests against wall surface  172 . Bolts  50  pass through holes  52  drilled at predetermined locations in wall surface  172 , as shown in  FIG. 16 . Wall-mounted folding table  170  can be constructed to remain in the folded state while supporting no or a light-weight object by use of a heavy weight or weighted table base  38  or by selection for spring bands  40  and  42  a material having a sufficiently low spring constant. Magnets  116  could be used to keep wall-mounted folding table  170  in the unfolded state. 
       FIGS. 18A and 18B  and  FIGS. 19A and 19B  are pairs of isometric and end views of a vertebral column  190 , which constitutes a first alternative embodiment of a vertebral column assembled with individual vertebral links interconnected by web sections confining expansion foam slats to form an integral distributed spring mechanism.  FIGS. 18A and 18B  show vertebral column  190  in a straightened, relaxed configuration, and  FIGS. 19A and 19B  show vertebral column  190  in a curved configuration assumed in response to an externally applied bending force. With reference to  FIGS. 18A ,  18 B,  19 A, and  19 B, vertebral column  190  includes nine parallel-aligned vertebral links, seven of which are interior vertebral links  192  of nominally the same size and shape and two of which are end-coupling vertebral links  194  and  196 . End-coupling vertebral links  194  and  196  are of the same size and shape of interior vertebral links  192 , except for formation of the respective U-shaped free ends  198  and  200  sized to receive different ones of seat mount  36  and seat (or table) base  38 . Each interior vertebral link  192  has on opposite sides and extending along its length two sets of complementary structures configured to interlock with corresponding complementary structures of next adjacent vertebral links  192 . End-coupling vertebral links  194  and  196  have on the sides opposite their respective free ends  198  and  200  structures configured to interlock with corresponding complementary structures of the next adjacent interior vertebral links  192 . The entire assembly of nine vertebral links forms articulating adjoining vertebral links. 
       FIGS. 20A and 20B  are respective isometric and end views of one interior vertebral link  192 , which is of I-beam shape with different structural features at its four lateral ends. Interior vertebral link  192  has on a seat side member  204  a first set of interlocking structures including an open-end hinge sleeve  206  and a pivot  208  and on an underside member  210  a second set of interlocking structures including a hooked end  212  and a rolled edge  214 . A web  216  interconnects seat side member  204  and underside member  210 .  FIGS. 18A and 18B  show end-coupling vertebral link  194 , on its seat side member  204 , open-end hinge sleeve  206  of the first set and, on its underside member  210 , hook and  212  of the second set.  FIGS. 18A and 18B  also show end-coupling vertebral link  196 , on its seat side member  204 , pivot  208  of the first set and, on its underside member  210 , rolled edge  214  of the second set. Vertebral links  192 ,  194 , and  196  are preferably made of extruded aluminum. 
       FIGS. 21A and 21B  and  FIGS. 22A and 22B  are pairs of enlarged fragmentary isometric and end views showing in detail the interconnection of multiple vertebral links to form vertebral column  190  of articulating adjoining vertebral links  192  and  196 . Each pair of adjacent vertebral links is pivotally joined by engagement of pivot  208  in hinge sleeve  206  and by compression of rolled edge  214  against hooked end  212  by an expansion foam or elastomeric slat  220  positioned between and contacting hooked end  212  and web  216 . Elastomeric slat  220  is preferably made of polyurethane foam of appropriate durometer and is of rectangular cross-sectional shape when at rest, i.e., before insertion between hooked end  212  and web  216  of adjacent vertebral links. Hinge sleeves  206  and pivots  208  arranged in alternating succession and each adjacent hinge sleeve  206  and pivot  208  connected to each other constitute interlocking articulating structures of vertical column  190  that establish its curvature.  FIGS. 21A and 21B  show vertebral column  190  in a straightened configuration corresponding to the unfolded state of folding seat  10 , and  FIGS. 22A and 22B  show vertebral column  190  in a curved configuration corresponding to the folded state of folding seat  10 . 
       FIGS. 21B and 22B  show elastomeric slats  220  exhibiting deformed, concave surfaces  222  that function as bearing surfaces against which hook ends  212  rest. Concave surfaces  222  change shape in response to changing compressive forces imparted by hook ends  212  so as to permit them to remain in place while complying with the different amounts of curvature of vertebral column  190  as it bends between the unfolding and folding states of folding seat  10 . Elastomeric slats  220  urge vertebral column  190  to its straightened configuration by inherent restorative forces of elastomeric slats  220  urging their return to a nominal rectangular shape in the absence of externally applied compressive forces during unfolding of folding seat  10 . If vertebral column  190  is used in the construction of wall-mounted table  170 , elastomeric slats  220  may be formed of softer (i.e., lower durometer) material to decrease its resistance to deformation and thereby cause wall-mounted table  170  to remain in the folded state when no object rests on the table surface. 
       FIG. 21B  shows the vertebral link dimensions and separation distances of adjoining vertebral links that establish for vertebral column  190  the progressive incremental angular displacements of pivots  208  interlocked within their associated hinge sleeves  206  to achieve the straightened configuration shown in  FIG. 18B  (unfolded state of folding seat  10 ) and the curved configuration of  FIG. 19B  (folded state of folding seat  10 ). With reference to  FIG. 21B , hooked end  212  and rolled edge  214  interlocked in the straightened configuration are separated by a distance  224  of 2.59 mm. A center-to-center distance  226  of open-end hinge sleeve  206  and pivot  208  of the first set of interlocking structures on underside member  210  of each interior vertebral link  192  is 19.7 mm. The width of vertebral column  190  is a distance  228  of 19.7 mm between the outer surfaces of seat side member  204  and underside member  210  of each of vertebral links  192 ,  194 , and  196 .  FIG. 22B  shows the complete closure of separation distance  224  and resulting contact between interlocked hooked end  212  and rolled edge  214  in the folded state of folding seat  10 . 
       FIGS. 23A and 23B  and  FIGS. 24A and 24B  are pairs of isometric and end views of a vertebral column  190 ′, which constitutes a second alternative embodiment of a vertebral column assembled with individual vertebral links interconnected by web sections confining expansion foam slats to form an integral distributed spring mechanism. The component parts of vertebral column  190  and vertebral column  190 ′ are the same, except for a modification of one of the first set of interlocking structures that decouples them and substitution of a larger rectangular elastomeric slat  220 ′ that fits between webs  216  of adjacent vertebral links. The views of vertebral column  190  and its components shown in  FIGS. 18A and 18B ,  FIGS. 19A and 19B ,  FIGS. 20A and 20B ,  FIGS. 21A and 21B , and  FIGS. 22A and 22B  correspond to the views of vertebral column  190 ′ and its components shown in the respective  FIGS. 23A and 23B ,  FIGS. 24A and 24B ,  FIGS. 25A and 25B ,  FIGS. 26A and 26B , and  FIGS. 27A and 27B . Similar components and structural features are identified by common reference numerals, and corresponding, modified components and features are identified by the same reference numerals followed by primes. 
     The modification of the first set of interlocking structures entails substitution of a rolled edges  212 ′ of vertebral links  192 ′ and  194 ′ for hooked ends  212  of vertebral links  192  and  194 . The substitution of rolled edge  212 ′ in each vertebral link  192 ′ and  194 ′ results in a decoupling of adjacent rolled edges  212 ′ and  214  of vertebral column  190 ′, as shown in  FIG. 23B . Rectangular elastomeric slat  220 ′ is sized to form a tight fit between webs  216  of adjacent ones of vertebral links  192 ′,  194 ′, and  196 ′, as shown in  FIGS. 23B and 26B .  FIGS. 24B and 27B  show that elastomeric slat  220 ′ undergoes compression on all sides in response to changing compressive forces imparted by different amounts of curvature of vertebral column  190 ′ as it bends between the unfolding and folding states of folding seat  10 . 
       FIG. 26B  shows the vertebral link dimensions and separation distances of adjoining vertebral links that establish for vertebral column  190 ′ the progressive incremental angular displacements of pivots  208  interlocked within their associated hinge sleeves  206  to achieve the straightened configuration shown in  FIG. 23B  (unfolded state of folding seat  10 ) and the curved configuration of  FIG. 24B  (folded state of folding seat  10 ). With reference to  FIG. 26B , adjacent rolled edges  212 ′ and  214  in the straightened configuration are separated by a distance  224 ′ of 2.59 mm. A center-to-center distance  226  of open-end hinge sleeve  26  and pivot  208  of the first set of interlocking structures on underside member  210  of each interior vertebral link  192  is 19.7 mm. The width of vertebral column  190 ′ is a distance  228  of 19.7 mm between the outer surfaces of seat side member  204  and underside member  210  of each of vertebral links  192 ′,  194 ′, and  196 ′.  FIG. 27B  shows the complete closure of separation distance  224 ′ and resulting contact between adjacent rolled edges  212 ′ and  214  in the folded state of folding seat  10 .  FIGS. 24B and 27B  show the convergence of adjacent rolled edges  212 ′ and  214  of vertebral column  190 ′ bent in the folded state of folding seat  10 . 
     End-coupling vertebral links  194  and  196  at opposite ends of vertebral column  190  and end-coupling vertebral links  194 ′ and  196 ′ at opposite ends of vertebral column  190 ′ each receive fasteners (not shown) to attach one of the end- coupling vertebral links to seat mount  36  and the opposite one of the end-coupling vertebral links to seat base  38  to form complete seat assemblies  24 . 
     It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. For example, substitution of a single, wide spring band for spring bands  40  and  42  may be acceptable in certain configurations of folding seat  10 . The scope of the present invention should, therefore, be determined only by the following claims.