Support structure for a seat back

A support structure for a seat back to simplify attachment of the seat back to a seat hinge. The seat back has a protrusion with a top surface and a bottom surface in which is drilled an insertion hole. The hinge has an insertion member that can be inserted into the insertion hole. When the insertion member is inserted in the insertion hole, attachment holes in the seat back and in the hinge become aligned, and the two parts can be easily fastened.

FIELD OF THE INVENTION 
The present invention relates to a support structure for a seat back. More 
particularly, the present invention relates to a structure to attach the 
back of an automobile rear seat to a hinge. 
DESCRIPTION OF RELATED ART 
As shown in FIG. 9 of the attached drawings, conventional automobile seat 
hinges 100 comprise a pair of left and right second brackets 102, that can 
be attached to a seat back 101, as well as a first bracket 103 that can be 
attached to the floor panel. Second brackets 102, and first bracket 103 
are joined together in a pivotable manner by an axle pin 104. Each of 
second brackets 102 is an integral body comprising an attachment member 
107 in direct contact with seat back 101. Each second bracket 102 has a 
central bolt hole 105 and an L-shaped hook 106 that extends in the length 
direction of the automobile. Substantially triangular support members 108 
are also part of second brackets 102. First bracket 103 is also a unitary 
body comprising an attachment member 110 in direct contact with the floor 
panel and having bolt holes 109), and a support member 111 extending 
upward from the lateral end of the attachment member 110. The support 
member 108 of the second bracket and the support member 111 of the first 
bracket are joined together by axle pin 104, so that they can rotate 
relative to each other. 
A rear seat back panel 112 is positioned across the back surface of the 
rear seat back 101. An attachment hole 113 extends through the rear seat 
back panel 112 and can be aligned with the bolt hole 105 of the second 
bracket. An insertion hole 114 for receiving the L-shaped hook 106 is also 
drilled in panel 112. 
To attach a seat hinge 100 having the conventional structure to a rear seat 
back 101, initially, the first bracket 103 is fastened to the floor panel 
with a bolt 115, and the hook 106 of the second bracket 102 is inserted 
into the insertion hole 114 of the rear seat back panel 112. Then, the 
rear seat back panel 112 attachment hole 113 is aligned with the bolt hole 
105 of the second bracket 102. The bolt 116 is inserted into and threaded 
into the attachment hole 113 through the bolt hole 105. In this manner the 
rear seat back 101 is attached to the floor panel, which is part of the 
main body of the automobile, via the seat hinge 100. 
Hook 106 is formed by press-bend tooling. Therefore, there is a concern 
about excessive variance in the gap or spacing L between the center of the 
bolt hole 105 and the hook 106 extending from attachment member 107 of the 
second bracket. If this gap L varies too much, it is possible that the gap 
M between the rear seat back panel insertion hole 114 and the attachment 
hole 113 will diverge from the aforementioned gap L, so that insertion of 
hook 106 in hole 114 will be impossible. By making the insertion hole 114 
large, a bolt 116 can be easily inserted even if there is some variance in 
the dimension L. 
The insertion hole 114 used in the conventional art is thus larger than the 
hook 106. Therefore, said hook 106 must be shifted around while being 
inserted into the insertion hole 114, so that the attachment hole 113 in 
the rear seat back panel 112 can be aligned with the second bracket bolt 
hole 105. Consequently, this arrangement does not facilitate alignment of 
the hook 106. Another problem occurs because the direction in which the 
hook 106 protrudes and the bolts 116 threading direction are both forward 
vis-a-vis the vehicle, so there is concern that the hook 106 will come 
unseated while the bolt is fastened. Because of these reasons it is 
difficult to maintain the rear seat back 101 in position while the hook 
106 is inserted in the rear seat back panel insertion hole 114, unless 
this is done after the rear seat cushion is in place. Thus, the 
conventional bracket is difficult to assemble. 
SUMMARY OF THE INVENTION 
The advantages and purpose of the invention will be set forth in part in 
the description which follows, and in part will be obvious from the 
description, or may be learned by practice of the invention. The 
advantages and purpose of the invention will be realized and attained by 
means of the elements and combinations particularly pointed out in the 
appended claims. 
The present invention was developed to address the problems described 
above. One objective of the present invention is thus to provide a seat 
back support structure which can be fastened to the back of a vehicle seat 
without having to maintain the seat cushion in place, because the seat 
hinge is held in a slot formed in the seat back, and retains the seat back 
in place during the assembly operation. 
To obtain these results, the lower rear surface of the seat back is 
provided with a protrusion having an insertion hole or cavity. The base of 
the seat hinge is attached to the floor panel, and an insertion member is 
provided on the tip of the hinge for insertion into the aforementioned 
insertion hole. By inserting the insertion member into the insertion hole 
of the seat back protrusion, the seat back is vertically supported by the 
seat hinge. In particular, by inserting the top end of the seat hinge 
which is already attached to the floor panel into an opening in the lower 
part of the seat back protrusion, the seat back is temporarily maintained 
in place by the hinge while the hinge is fastened to the seat back, thus 
facilitating assembly of the seat. 
In one embodiment of the present invention, a protrusion with a top surface 
and a bottom surface is provided on the rear surface of the seat back. An 
insertion hole is perforated in the lower surface of said protrusion. 
Primary attachment holes are perforated at a location below the 
protrusion, on the aforementioned rear surface. The base of the seat hinge 
is attached to the floor panel, and an insertion member designed to be 
inserted into the aforementioned insertion hole is provided on the tip of 
the hinge. Secondary attachment holes corresponding to the aforementioned 
primary attachment holes are perforated below the aforementioned insertion 
member. When the seat back is mounted, the insertion member is inserted 
into the insertion hole of the protrusion, so that the tip of the 
insertion member directly abuts from below the top surface of the 
protrusion. In this position, the seat back rests on the seat hinge, so 
that the primary and secondary attachment holes are essentially aligned in 
the vertical direction. 
Fastening members, such as bolts, are inserted through these primary and 
secondary attachment holes, so that the seat back and the seat hinge are 
attached together. For example, threads can be tapped, or a nut can be 
welded within the primary attachment holes so that a threaded fastener can 
be used. Thus, by simply inserting the tip of the seat hinge into the seat 
back insertion hole, the seat back and seat hinge attachment holes can be 
located in the proper alignment. 
In another embodiment according to the present invention, the insertion 
hole is formed of a width approximately equal to the width of the 
insertion member. The distance between the top surface of the seat back 
protrusion and the primary attachment holes on the seat back is 
approximately equal to the distance between the tip of the insertion 
member and the secondary attachment holes formed on the seat hinge. With 
this seat hinge structure, when the insertion member is introduced into 
the insertion hole of the seat back protrusion, the tip of the insertion 
member rests against the underside of the protrusion's top surface, so 
that the primary attachment holes and the secondary attachment holes are 
vertically aligned, and are also centered with respect to the vehicle 
width. As a result, the vertical and horizontal alignment of the primary 
and secondary attachment holes is performed automatically once the seat 
back protrusion hole is placed over the seat hinge insertion member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference will now be made in detail to the present preferred embodiments 
of the invention, examples of which are illustrated in the accompanying 
drawings. Wherever possible, the same reference numbers will be used 
throughout the drawings to refer to the same or like parts. 
FIG. 1 shows a seat hinge 1 and a rear seat 2 according to a first 
embodiment of the invention. Rear seat 2 comprises a rear seat cushion 4 
placed atop the surface of the floor panel 3, and a pair of left and right 
rear seat backs 5 attached so they can be pivoted up or down about a seat 
hinge 1, which is located in the back part of said rear seat cushion 4. 
Rear seat backs 5 can rotate, separately and independently, about an axis 
along the width of the vehicle body. Also, rear seat back panels 6 are 
arranged or the back surfaces of said rear seat backs 5, and the surfaces 
of the rear seat backs 5 are covered with a covering 7. 
A perspective enlargement of the seat hinge 1 of FIG. 1 is shown in FIG. 2. 
The seat hinge 1 shown in FIG. 2 is provided with a first bracket 9 
secured to the floor panel 3 using bolts 8, and left and right second 
brackets 10 located above the first bracket 9 and attached to the first 
bracket 9 by a pin 11 that pivotally supports the first bracket 9 and the 
second brackets 10. The first bracket 9 directly touches the floor panel 
3, and the lateral end of bracket 9 includes an attachment member with a 
flange 12 integral with support member 14 which extends upwards opposite 
to support member 14 from said attachment member 13. Two individual bolt 
holes 15 are provided in the aforementioned attachment member 13. Second 
brackets 10 directly touch the rear seat back panel 6 and comprise an 
attachment member 17 with secondary attachment holes 16 and a support 
member 18 positioned to extend orthogonally vis-a-vis the lateral end of 
said attachment member. The tip of the attachment member 17 is formed as 
an insertion member 19 having a width W narrower than the overall width of 
the attachment member 17. 
A protrusion 20 extends from the rear seat back toward the rear of the 
vehicle and forms an integral unit with the rear seat back panel 6 at a 
location facing the aforementioned seat hinge. Protrusion 20 comprises 
rear face 21, top face 22, two side faces 23, and a bottom face 24. An 
insertion hole 25 is formed on bottom face 24, defining a receptacle or 
cavity in which insertion member 19 can be inserted. The width X of 
insertion hole 25 approximately equals the width W of the insertion member 
19. Primary attachment holes 26 are perforated in the rear seat back panel 
6 below the protrusion 20, in alignment with the secondary attachment 
holes 16. 
As shown in FIG. 3, the seat hinge includes a first bracket 9 that is 
bifurcated and affixed to the front surface 27 and the top surface 28 of 
the floor panel 3 by bolts 8. Second brackets 10 are designed to rotate 
vis-a-vis the first bracket 9, by pivoting on a pin 11. 
As shown in FIG. 2, the distance Y between the top edge of the protrusion 
rear face that is provided on the rear seat back panel 6 and the center of 
a primary attachment hole 26, approximately equals the distance Z between 
the tip of the insertion member 19 of the second bracket 10 and the center 
of a secondary attachment hole 16. When the insertion member 19 of the 
second bracket 10 is introduced into the insertion hole 25 of the 
protrusion 20 on the rear seat back panel 6, the tip 30 of the insertion 
member 19 rests against the underside of top edge 29 of protrusion 20, so 
that the primary attachment holes 26 of the rear seat back panel 6 are 
aligned with the secondary attachment holes 16 of the second bracket 10. 
In addition, the distance P between the inside surface of rear face 21 and 
the surface of the rear seat back panel 6 approximately equals the plate 
thickness T of the insertion member 19 of the second bracket 10. In a 
preferred embodiment, nuts 31 are affixed to the back surface of the 
primary attachment holes 26 of the rear seat back panel 6. 
To attach the rear seat back 5 to a seat hinge 1, initially, the seat hinge 
first bracket 9 is fastened to the floor panel 3, for example, by a bolt. 
Then, after the back of the rear seat 5 has been lifted above the seat 
hinge 1, it is lowered over the said seat hinge 1, so that the insertion 
hole 25 of the protrusion 20 located in the rear seat back panel 6 fits 
around the insertion member 19 of the seat hinge 1. After this operation, 
the primary attachment holes 26 of the rear seat back panel 6 are nearly 
aligned with the secondary attachment holes 16 of the second bracket 10, 
while seat back 5 is held up by seat hinge 1. Thus, by inserting bolts 
into these attachment holes 26, 16 and fastening them, the rear seat back 
5 can be attached to the seat hinge 1. 
With the structure according to the invention, as shown in FIGS. 2 and 4, 
the distance Y of the protrusion 20 on the rear seat back panel 6 is 
formed to approximately equal the distance Z of the second bracket 10. 
Also, because the width X of the insertion hole 25 approximately equals 
the width W of the insertion member 19, inserting the insertion member 19 
into insertion hole 25 results in the approximate alignment of the primary 
attachment holes 26 of the rear seat back panel 6 with the secondary 
attachment holes 16 of the second bracket. The procedure of attaching the 
rear seat back 5 is thus simplified. In addition, the threading direction 
of the bolts 32 is essentially orthogonal to the direction of insertion of 
the insertion member, therefore tightening the bolts will not easily cause 
the insertion member 19 to become dislodged from the insertion hole 25. 
In FIGS. 5-8, a seat hinge 33 and a rear seat 2 according to a second 
embodiment of the invention are shown. 
As shown in FIG. 5, seat hinge 33 is attached to the floor panel 3 and 
includes insertion members 19 extending from the top of the hinge. A 
protrusion 20 having an insertion hole 25 is provided on the rear seat 
back panel of each rear seat back. By inserting the insertion member 19 
into the insertion hole 25, the rear seat back 5 can be positioned and 
attached to the seat hinge 33. Since many components of the second 
embodiment are analogous to the seat hinge 1 and the rear seat 2 of the 
first embodiment described above, the same reference numeral are used for 
similar parts. 
As shown in FIG. 6, the seat hinge 33 is provided with a first bracket 9 
fastened by bolts to the floor panel, second brackets 10, attached on the 
left and right sides straddling said first bracket 9, and a pin 11 to 
pivotally support both brackets 9, and 10 so they may rotate relative to 
one another. The first bracket 9 is preferably an integral body directly 
in contact with the floor panel, comprising an attachment member with bolt 
holes 15 and a support member 14 that is essentially of triangular shape 
and extends up from the lateral end of said attachment member 13. Each of 
the second brackets 10 is also preferably an integral body comprising an 
attachment member 17 having secondary bolt holes 16, that is in direct 
contact with the corresponding rear seat back panel 6. The second bracket 
includes an approximately triangularly shaped support member 18 that 
extends orthogonally vis-a-vis the lateral end of said attachment member 
17. The tip of the attachment member 17 of the second bracket 10 includes 
an insertion member whose width W is smaller than the overall width of the 
second bracket. As shown in FIG. 7, seat hinge 33 is designed so that the 
first bracket 9 is attached by bolts to the planar floor panel 3, and the 
second bracket 10 can rotate about a pin 11. 
As shown in FIG. 6, a substantially boxlike protrusion 20 extends backwards 
from each seat back panel, and forms an integral body with said rear seat 
back panel. The bottom of said protrusion 20 opens to form an insertion 
hole 25. This protrusion 20 comprises a rear face 21 approximately 
parallel to the rear seat back panel 6, a top face 22, and two lateral 
faces 23. As shown in FIG. 8, the gap P between the rear surface of said 
rear face 21 and the surface of the rear seat back panel 6 is 
approximately equal to the plate thickness T of the insertion member 19 of 
the second bracket 10. Also, the distance Z between the tip of the 
insertion member 19 of the second bracket 10 and the center of a secondary 
attachment hole 16 is approximately equal to the gap Y between the rear 
edge of the top face 22 of the aforementioned protrusion 20 and the center 
of a primary attachment hole 26. The width W of the insertion member 19 of 
the second bracket and the width X of the protrusion insertion hole 25 are 
formed to be approximately identical. 
The procedure for attaching the rear seat back 5 to the seat hinge 33 is 
analogous to that discussed earlier for the first embodiment. Insertion 
member 19 of the seat hinge 33 is inserted into insertion hole 25 of the 
protrusion 20 provided in the rear seat back panel 6. After the primary 
attachment holes 26 of the rear seat back panel 6 and the secondary 
attachment holes 16 of the seat hinge 33 are aligned, bolts 32 are 
inserted through these attachment holes 26, 16, and are fastened. The 
procedure is repeated for each of the two seat backs 5. 
Because of the support structure according to the invention, the primary 
attachment holes 26 of the rear seat back panel 6 can be substantially 
aligned with the positions of the attachment holes 16 of the second 
brackets 10 by simply inserting the insertion member 19 of the seat hinge 
33 into the insertion hole 25. The process of attaching the rear seat back 
5 thus becomes easy. Also, because the bolts fasten in a direction more or 
less orthogonal to the direction of insertion of the insertion member, 
insertion member 19 will not easily become dislodged from the insertion 
hole 25 while the bolts are being fastened. 
Various transformations and modifications of the described embodiments are 
possible based on the technical concepts disclosed in the present 
invention. For example, in the embodiments of the invention described, the 
protrusion 20 is formed as one part with the rear seat back panel 6. 
However, the protrusion 20 can also be manufactured separately and later 
attached to the rear seat back panel 6 by commonly used means, such as 
welding. 
As described above, the support structure for a seat back according to the 
present invention includes a protrusion with an insertion hole on its 
bottom surface the is provided on the rear surface of each seat back. The 
base of the seat hinge is attached to the vehicle floor panel, and an 
insertion member is provided on the tip of the hinge, for insertion in the 
insertion hole of each protrusion. By inserting the insertion member into 
the insertion hole of the protrusion, the seat back is supported by, the 
seat hinge. Because of the hinge design, when the seat back is fastened to 
the seat hinge, the insertion member does not easily disengage from the 
insertion hole. 
In another embodiment according to the present invention, a protrusion 
having ,a top and a bottom surface is provided on the rear face of the 
seat back, and an insertion hole is formed on the bottom surface of said 
protrusion. Primary attachment holes are drilled below the protrusion, on 
the rear surface of the seat back. The base of the seat hinge is attached 
to the floor panel, and an insertion member that can be inserted into the 
aforementioned insertion hole is provided on the top of the hinge. 
Secondary attachment holes corresponding to the aforementioned primary 
attachment holes are drilled below the insertion member. By simply 
inserting the insertion member into the insertion hole of the protrusion 
until the tip of the insertion member abuts against the protrusion's top 
surface, the vertical positioning and alignment of the primary attachment 
holes with the secondary attachment holes is assured. In this manner 
assembly line workers can easily attach the seat back to the seat hinge 
without having to align the locations of the attachment holes by hand. 
Because the insertion member does not easily disengage from the insertion 
hole, the task of attaching the seat back to the seat hinge is simplified, 
even if the seat cushion is of a non-removable type. Moreover, when bolts 
are inserted into and fastened in the attachment holes, the load carried 
by the bolts is less than that in conventional arrangements because the 
hinge insertion member vertically holds the seat back, and therefore this 
invention provides also an advantage in terms of strength of the support. 
In yet another embodiment according to the invention, the width of the 
insertion holes approximately equals the width of the insertion members. 
Additionally, the gap between the top face of the protrusion and a primary 
attachment hole approximately equals the gap between the tip of the 
insertion member and the secondary attachment hole. Therefore, by simply 
inserting the insertion member into the insertion hole of the protrusion, 
the tip of the aforementioned insertion member abuts the top surface of 
the protrusion, and the vertical position within the vehicle and alignment 
of the primary attachment holes with the secondary attachment holes is 
assured. Thus, the process of attaching a seat back to a seat hinge is 
simplified. 
It will be apparent to those skilled in the art that various modifications 
and variations can be made in the seat hinge of the present invention 
without departing from the scope or spirit of the invention. 
Other embodiments of the invention will be apparent to those skilled in the 
art from consideration of the specification and practice of the invention 
disclosed herein. It is intended that the specification and examples be 
considered as exemplary only, with a true scope of the invention being 
indicated by the following claims.