Seat cushion structure

A seat cushion is disclosed which comprises a rectangularly extending frame having opposed side portions; a flat sheet member arranged within a space defined by the rectangular frame; connecting devices for connecting each side portion of the flat sheet member to one of the opposed side portions of the frame; a plastic panel member having side portions raised, the plastic member being disposed on the flat sheet member leaving between each of the raised side portions and corresponding one of the opposed side portions of the frame a generally wedge-shaped clearance; a cushion structure tightly mounted on the plastic panel in such a manner that side portions of the cushion structure are raised by the raised side portions of the plastic panel; and two cushion pad units respectively received in the wedge-shaped clearances defined below the raised side portions of the plastic panel member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates in general to a seat for a motor vehicle, and 
more particularly to a seat cushion of the seat which has spaced side 
portions raised for providing a seat occupant with a comfortable sitting 
posture. 
2. Description of the Prior Art 
Hitherto, various types of automotive seats have been proposed and put into 
practical use for the purpose of providing a seat occupant with a 
comfortable and stable sitting posture. In particular, various measures 
have been applied to the seat to lighten the fatique of the seat occupant 
when he or she is sitting on the seat for a long time. One of the measures 
is to provide a seat cushion with largely raised side portions of pad 
material. 
The seat cushion of this type comprises a rectangular frame, a plate member 
held by and extending within the frame, a plastic panel seated on the 
plate member, a cushion pad entirely mounted on both the frame and the 
plastic panel, and an outer layer member covering the cushion pad. For 
formation of the raised side portions on the seat cushion, the plastic 
panel is molded to have raised or swelled side portions, and the amount of 
pad material put on such raised portions is somewhat increased. 
However, due to its inherency in construction, the above-mentioned seat 
cushion has such the following drawbacks. 
That is, for providing the raised side portions with a desired pliability, 
a greater amount of pad material must be put into given portions, by 
manual labor, where the raised side portions are to be provided. This may 
cause unbalanced configulations and sizes of the raised side portions. 
This further induces highly costed production of the seat. Furthermore, 
putting the pad material into the given portions requires the employment 
of skilled labor and time. Furthermore, the seat cushion of this type is 
forced to produce unsightly creases or wrinkles on the outer layer member 
when bearing a seat occupant. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a seat 
cushion which is free of the above-mentioned drawbacks. 
According to the present invention, there is provided a seat cushion which 
comprises a rectangularly extending frame having opposed side portions; a 
flat sheet member arranged within a space defined by the rectangular 
frame; connecting means for connecting each side portion of the flat sheet 
member to one of the opposed side portions of the frame; a plastic panel 
member having side portions raised, the plastic member being disposed on 
the flat sheet member leaving between each of the raised side portions and 
corresponding one of the opposed side portions of the frame a generally 
wedge-shaped clearance; a cushion structure tightly mounted on the plastic 
panel in such a manner that side portions of the cushion structure are 
raised by the raised side portions of the plastic panel; and two cushion 
pad units respectively received in the wedge-shaped clearances defined 
below the raised side portions of the plastic panel member.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1 and 2, particularly FIG. 1, there is shown but 
partially a seat cushion 1A of a first embodiment of the present 
invention. 
The seat cushion 1 comprises a rectangularly extending frame 2 which is 
constructed of a metal pipe. A rectangular flexible sheet 4 extends within 
the rectangular frame 2 and is resiliently held by the same through a 
plurality of metal hooks 3a. That is, the sheet 4 is formed at each side 
thereof with a folded-back portion or sleeve portion 4a through which a 
steel rod 3 is inserted. Axial ends of the steel rod 3 are left free. The 
rectangular flexible sheet 4 is arranged within the rectangular frame 2 
having the steel rods 3 faced toward opposed side portions of the frame 2 
respectively. The steel rods 3 and the side portions of the frame 2 are 
connected through the hooks 3a, each having one curved end hooked to the 
corresponding steel rod 3 and the other curved end hooked to the 
corresponding side porition of the frame 2. More specifically, the other 
curved ends of tghe hooks 3a are hooked to openings (no numerals) formed 
in the frame 2. With this arrangement, the flexible sheet 4 is resiliently 
expanded within the rectangular frame 4. A generally rectangular plastic 
panel 5 is mounted on the expanded flexible sheet 4. Preferably, the panel 
5 is made of a thermoplastic resin having a suitable resiliency. Mounted 
on the panel 5 is a cushion structure 8 which is of a layered article 
comprising a pad material 6 and an outer layer member 7. The pad material 
6 is constructed of foamed polyurethane, foamed rubber or the like. The 
outer layer member 7 comprises a backing material 7a, a wadding 7b and an 
outer skin 7c. 
In accordance with the present invention, the following measures are 
further employed. 
That is, the pad material 6 is molded to have a convex structure having 
side portions raised as is seen from FIG. 1. For neatly supporting thereon 
the convex pad material 6, the plastic panel 5 is also formed convex 
having side portions 5b raised. An integral side wall 5a extends 
downwardly from the leading end of each raised side portion 5b of the 
plastic panel 5. That is, as shown, the side wall 5a extends outside the 
corresponding side portion of the frame 2 and has a lower end portion bent 
inwardly, that is, toward the frame 2. Thus, a considerable clearance of 
generally triangular cross section is defined below each side of the 
plastic panel 5, which is bounded by the raised side portion 5b, the upper 
part of the side wall 5a and an imagninary plane which includes the 
expanded flexible sheet 4. 
Two wedge-shaped air bags 10 are respectively received in the clearances 
which are thus provided at the lateral sides of the plastic panel 5. The 
air bags 10 are constructed of plastic film, rubber or the like. In order 
to fix the shape of the bag 10 under expansion, the bag 10 may be jacketed 
with a reinforcing cloth 10a. Designated by numerals 10b are double-faced 
adhesive members by which the air bag 10 is affixed to the plastic panel 5 
and the expanded flexible sheet 4. 
As in seen from FIG. 1, the outer skin 7c of the outer layer member 7 
extends downward in a manner to cover the downwardly extending side wall 
5a of the plastic panel 5. The lower end portion of the outer skin 7c is 
folded back and fixed to the lower end of the panel side wall 5a by means 
of retainers 9a. Designated by numeral 9b ar other retainers by which a 
given portion of the cushion structure 8 is fixed to the raised side 
portion 5b of the plastic panel 5. Due to presence of the downwardly 
extending part of the outer skin 7c which conceals the unsightly parts, 
the external view of the seat cushion 1 is improved. 
If desired, as is shown in FIG. 3, a generally U-shaped air bag 10 may be 
used in place of the above-mentioned two air bags 10. In this 
modification, the pad material 6 and the plastic panel 5 are molded to 
have generally U-shaped recesses respectively for accommodating the air 
bag 10. Furthermore, a doughnut-like air bag is also usable. 
Referring to FIG. 4, there is shown a second embodiment of the present 
invention. In the seat cushion 1B of this embodiment, foamed plastic 
members 11, such as polyurethane foam or the like, are used in place of 
the above-mentioned air bags 10. That is, the foamed plastic members 11 
are received in the clearances which are provided at the lateral sides of 
the plastic panel 5. As shown, each foamed plastic member 11 is bonded to 
the plastic panel 5 and seated on a supporting plate 12 which is mounted 
on the frame 2, the hooks 3a and the side portion of the expanded flexible 
sheet 4. 
Referring to FIG. 5, there is shown a third embodiment of the present 
invention. The seat cushion 1C of this embodiment is substantially the 
same as that of the second embodiment except that in the third embodiment, 
plastic holders 13 are employed in place of the above-mentioned hooks 3a 
for connecting the flexible sheet 4 to the frame 2. That is, the plastic 
holders 13 are integrally connected to the sheet 4 and hooked to the frame 
2, and the foamed plastic member 11 is seated on the side portion of the 
sheet 4. 
Referring t6o FIGS. 6 and 7, there is shown a fourth embodiment of the 
present invention. The seat cushion 1D of this embodiment is substantially 
the same as the seat cushion 1A of the first embodiment of FIG. 1 except 
that in the fourth embodiment, a sleeve 14 made of flexible woven cloth, 
flexible plastic sheet or the like is employed, which holds therein the 
air bag 10. As is seen from FIG. 7, the sleeve 14 is stitched to the 
flexible sheet 4. In this fourth embodiment, undesired slippage and 
dislocation of the air bag 10 are assuredly prevented due to the provision 
of the sleeve 14. 
If desired, the following modifications are employable in the present 
invention. 
The downwardly extending part of the outer skin 7c may be removed. In this 
case, the outer surface of the downwardly extending side wall 5a of the 
plastic panel 5 is lined with a suitable layer which has an external view 
similar to the outer layer member 7. 
A separate panel may be used as a substitute for the downwardly extending 
part 5a of the plastic panel 5. Of cource, in this case, the separate 
panel is fixed to the plastic panel 5 through suitable connectors. 
In the following, advantages of the present invention will be described. 
First, in the present invention, an air bag 10 or foamed plastic member 11, 
which can have a fixed configulation and a uniformed size, is used for 
providing the seat cushion with raised side portions. Thus, the raised 
side portions formed on the seat cushion can be balanced in configulation 
and size. This provides not only improvement in extenal view of the seat 
cushion but also improvement in occupant holding performance. 
Second, since the air bag 10 and the foamed plastic member 11 are of a 
single unit, putting them into the given clearances of the seat cushion 
structure can be easily achieved without employment of skilled labor and 
time. 
Third, since the cushion structure 8 including the pad material 6 and the 
outer layer member 7 has a generally even thickness therethroughout, 
formation of the same can be easily carried out. 
Fourth, since the downwardly extending part of the outer skin 7c of the 
outer layer member 7 is fixed at vertically spaced two portions thereof to 
the side wall 5a of the plastic panel 5, the outer skin 7c is prevented 
from producing unsightly creases or wrinkles thereon even when the seat 
cushion bears a seat occupant.