U.S. patent application number 13/216427 was filed with the patent office on 2012-03-01 for seat device having a function of retaining person's seated position.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Hiroshi INOU, Hiroyuki Mishima, Kenichi Muraguchi, Hisako Nomura, Mamoru Sawada, Seiji Totsuka.
Application Number | 20120049595 13/216427 |
Document ID | / |
Family ID | 44674317 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120049595 |
Kind Code |
A1 |
INOU; Hiroshi ; et
al. |
March 1, 2012 |
SEAT DEVICE HAVING A FUNCTION OF RETAINING PERSON'S SEATED
POSITION
Abstract
A seat device has an upper body support member having an upper
body support surface that supports an upper back of a person. The
support surface has aid ridges for shoulder blades. The aid ridges
are located to be fit to a range of fifth to seventh ribs of the
ribs in a vertical direction of the seat member, and are
substantially horizontal in a width direction of the seat device.
The support surface is located such that a length from a center
line of the support surface in a width direction thereof to a
center-line-side end of each of the aid ridges is equal to or
larger than a length from a backbone center line to a backbone end
of the person and equal to or smaller than a length from the
backbone center line to a shoulder blade of the person.
Inventors: |
INOU; Hiroshi; (Kariya-shi,
JP) ; Sawada; Mamoru; (Yokkaichi-shi, JP) ;
Totsuka; Seiji; (Tokai-shi, JP) ; Nomura; Hisako;
(Osaka, JP) ; Muraguchi; Kenichi; (Itami-shi,
JP) ; Mishima; Hiroyuki; (Tokyo, JP) |
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
44674317 |
Appl. No.: |
13/216427 |
Filed: |
August 24, 2011 |
Current U.S.
Class: |
297/284.1 ;
297/452.29 |
Current CPC
Class: |
B60N 2/643 20130101;
B60N 2/646 20130101 |
Class at
Publication: |
297/284.1 ;
297/452.29 |
International
Class: |
A47C 7/46 20060101
A47C007/46; A47C 7/40 20060101 A47C007/40 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2010 |
JP |
2010-188421 |
Claims
1. A seat device capable of retaining a person's seated position,
comprising: an upper body support member having an upper body
support surface that supports an upper body back of a person to be
seated on the seat device, wherein the upper body support surface
has aid ridges for shoulder blades, the aid ridges i) being located
to be fit to a range of fifth to seventh ribs of the ribs in a
vertical direction of the seat member, ii) being substantially
horizontal in a width direction of the seat device, and iii) being
located such that a length from a center line of the upper body
support surface in a width direction thereof to a center-line-side
end of each of the aid ridges is equal to or larger than a length
from a backbone center line to a backbone end of the person and
equal to or smaller than a length from the backbone center line to
a shoulder blade of the person.
2. The seat device of claim 1, comprising a seat member having a
seat surface on which the person is seated.
3. The seat device of claim 1, wherein the upper body support
surface has horizontal ridges for lower ribs, the horizontal ridges
i) being located to be fit to a range of tenth to twelfth ribs of
the ribs in the vertical direction and ii) being substantially
horizontal to the seat surface.
4. The seat device of claim 2, wherein the upper body support
surface has a pair of support projections for ilia, which are fit
to a pair of ilium projections of the person, the ilium projections
being projected rearward when the person is seated on the seat
surface of the seat member, and the seat surface has a pair of
accommodating recesses for ischiums, which accommodates therein a
pair of ischium projected portions of the person, the ischium
projected portions being projected downward.
5. The seat device of claim 1, wherein the upper body support
surface has slant ridges for ribs, the slant ridges touching the
ribs of the person from beneath and being slanted according to the
ribs, the ribs descending with person's exhalation.
6. The seat device of claim 5, wherein the slant ridges are formed
to touch a person's upper body back between a ninth rib and a tenth
rib of the ribs.
7. The seat device of claim 2, wherein the seat surface has a pair
of reference ridges each of which is fit to a recess between a
biceps femoris muscle and a semimembranosus muscle of each of
thighs of the person.
8. The seat device of claim 2, wherein the upper body support
member is configured such that at least an upper part of the upper
body support member is movable to the seat surface in the vertical
direction, the upper part being higher than lower ends of the aid
ridges for the shoulder blades.
9. The seat device of claim 8, wherein the upper body support
surface has horizontal ridges for lower ribs, the horizontal ridges
i) being located to be fit to a range of tenth to twelfth ribs of
the ribs in the vertical direction and ii) being substantially
horizontal to the seat surface, and the upper body support member
is configured such that at least an upper part of the upper body
support member is movable to the seat surface in the vertical
direction, the upper part being higher than lower ends of the
horizontal ridges for the lower ribs.
10. The device of claim 8, wherein the upper body support surface
has slant ridges for ribs, the slant ridges touching the ribs of
the person from beneath and being slanted according to the ribs,
the ribs descending with person's exhalation, and the upper body
support member is configured such that at least an upper part of
the upper body support member is movable to the seat surface in the
vertical direction, the upper part being higher than lower ends of
the slant ridges for the ribs.
11. The seat device of claim 10, wherein the upper body support
surface has horizontal ridges for lower ribs, the horizontal ridges
i) being located to be fit to a range of tenth to twelfth ribs of
the ribs in the vertical direction and ii) being substantially
horizontal to the seat surface, and the upper body support member
is configured such that at least an upper part of the upper body
support member is movable to the seat surface in the vertical
direction, the upper part being higher than lower ends of the
horizontal ridges for the lower ribs.
12. A seat device capable of retaining a person's seated position,
comprising: a seat member having a seat surface on which a person
is seated; and an upper body support member having an upper body
support surface that supports an upper body back of the person,
wherein the upper body support surface has a pair of substantially
horizontal ridges which are located on both sides of a center line
of the upper body support surface in a width direction thereof, and
the upper body support member is configured such that at least an
upper part of the upper body support member is movable to the seat
surface in the vertical direction, the upper part being higher than
lower ends of the pair of substantially horizontal ridges.
13. The seat device of claim 12, wherein the upper body support
surface has a pair of slant ridges which are slanted at an angle
substantially equal to an inclination angle of the ninth or tenth
rib of the person, the slant ridges being located on both sides of
a center line of the upper body support surface in a width
direction thereof and being slanted as advancing from the center
line, and the upper body support member is configured such that at
least an upper part of the upper body support member is movable to
the seat surface in the vertical direction, the upper part being
higher than either lower ends of the pair of substantially
horizontal ridges or lower ends of the pair of slant ridges.
14. The seat device of claim 13, wherein the pair of substantially
horizontal ridges is a pair of substantially horizontal ridges
located lower than the pair of slant ridges.
15. The seat device of claim 8, wherein the upper body support
surface has a pair of support projections for ilia, which are fit
to a pair of ilium projections of the person, the seat surface has
a pair of accommodating recesses for ischiums, which accommodates
therein a pair of ischium projected portions of ischia of the
person, and the upper body support member has a portion in which
the pair of support projections for the ilia are provided on the
upper body support surface, the portion of the upper body support
member being inseparable from the seat member providing the seat
surface.
16. A device capable of retaining a person's seated position,
comprising: an upper body support surface that supports an upper
body back of a person to be seated, wherein the upper body support
surface has aid ridges for shoulder blades, the aid ridges i) being
located to be fit to a range of fifth to seventh ribs of the ribs
in a vertical direction of the device, ii) being substantially
horizontal in a width direction of the device, and iii) being
located such that a length from a center line of the upper body
support surface in a width direction thereof to a center-line-side
end of each of the aid ridges is equal to or larger than a length
from a backbone center line to a backbone end of the person and
equal to or smaller than a length from the backbone center line to
a shoulder blade of the person.
17. The device of claim 16, comprising a seat surface on which the
person is seated, wherein the upper body support surface has
horizontal ridges for lower ribs, the horizontal ridges i) being
located to be fit to a range of tenth to twelfth ribs of the ribs
in the vertical direction and ii) being substantially horizontal to
the seat surface.
18. The device of claim 17, wherein the upper body support surface
has a pair of support projections for ilia, which are fit to a pair
of ilium projections of the person, the ilium projections being
projected rearward when the person is seated on the seat surface,
and the seat surface has a pair of accommodating recesses for
ischiums, which accommodates therein a pair of ischium projected
portions of the person, the ischium projected portions being
projected downward.
19. The seat device of claim 16, wherein the upper body support
surface has slant ridges for ribs, the slant ridges touching the
ribs of the person from beneath and being slanted according to the
ribs, the ribs descending with person's exhalation.
20. The seat device of claim 19, wherein the slant ridges are
formed to touch a person's upper body back between a ninth rib and
a tenth rib of the ribs.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on and claims the benefit of
priority from earlier Japanese Patent Application No. 2010-188421
filed Aug. 25, 2010, the description of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field of the Invention
[0003] The present invention relates to a seat device having a
function of retaining a person's seated position, and in
particular, the seat device which can be realized as seats for
vehicles, for example.
[0004] 2. Related Art
[0005] It is known that chairs are widely used as seated position
retention devices. Such a chair includes a seat member on which a
person is seated and an upper body support member that supports the
upper back of the person. It is also known to use items for
covering a chair and placed on a chair. In order to allow a person
to be seated with ease, various suggestions have been made
regarding the shapes of these seated position retention
devices.
[0006] For example, a patent document JP-A-H07-315089 discloses a
pelvis support mechanism for vehicle seats. In this mechanism, a
seat back (upper body support member) is divided into two members
of an upper back and a lower back, and the lower back is made
rotatable at a level corresponding to a lumbar support position.
Thus, the angle of the lower back in this mechanism is made
adjustable to match a hip point of a seated person, so that the
person will not get easily tired. Another type of various seated
position retention devices is also known, which include a side
support mechanism that supports a seated person from both sides to
make the person physically immovable.
[0007] The adjustment of the angle of the lower back as disclosed
in the above patent document will not suppress horizontal imbalance
of a seated person's posture. Thus, the technique disclosed in this
patent document causes a seated person's posture to be imbalanced
in the horizontal direction and this imbalanced posture may be a
posture that easily fatigues the seated person.
[0008] It is true that a side support mechanism is able to support
a seated person's posture but the support of the posture is
forceful.
[0009] Therefore, depending on the conditions, the degree of
freedom of the physical motion is lowered. For this reason, muscle
stress is likely to be caused in the body trunk, the upper legs and
the lower legs, leading to accumulation of fatigue.
SUMMARY
[0010] Hence it is desired to provide a seated position retention
device and a seat device which are able to suppress a horizontal
imbalance of a seated person's posture.
[0011] In the present disclosure, "retaining a person's seated
position" intends to mean "assisting a person to retain their
seating position."
[0012] In order to achieve the above object, the present disclosure
provides a seat device for retaining a person's seated position, of
which technical concept can also be practiced as a seated position
retention device. In this column, the seat device is representative
both devices. According to a first aspect of the present
disclosure, the seat device includes an upper body support surface
which is provided with shoulder blade aid ridges (or simply aid
ridges). The shoulder blade aid ridges are positioned in a vertical
range covering the fifth to the seventh ribs. The shoulder blade
aid ridges are substantially horizontal and each of them has a
backbone-side end portion positioned between the backbones and the
corresponding shoulder blade.
[0013] Since the shoulder blade aid ridges are substantially
horizontally provided, the shoulder blade aid ridges hinder a
tilting motion of a seated person's upper body in the horizontal
direction. Accordingly, horizontal imbalance of the person's
posture is suppressed.
[0014] It should be appreciated that a rotational motion of the
upper body backbones is not hindered by the shoulder blade aid
ridges. Accordingly, when a seated person looks left or right, the
horizontal sway of the upper body is suppressed, while the
rotational motion of the upper body for turning the person's face
to the left or right is accelerated. Since horizontal sway of the
head during driving is not favorable, the seat device of the
present disclosure is favorably used for a driver's seat.
[0015] When the shoulder blade aid ridges are provided, each of the
backbone-side end portions of the ridges is positioned between
backbones and a backbone-side end of the corresponding shoulder
blade. Thus, the backbone-side end portion of each ridge is used as
a fulcrum of turn of the corresponding shoulder blade to aid the
turning of the shoulder blade. Accordingly, the motion of the
shoulders accompanying the turning of the shoulder blades becomes
easy. Thus, when the seat device of the present disclosure is used
for a driver's seat of a vehicle, handling of the steering wheel
becomes easy.
[0016] Shoulder blades are pulled downward by lower trapezius
muscles. Meanwhile, shoulder blades are supported by the respective
shoulder blade aid ridges. Therefore, the trapezius muscles are
suppressed from being lowered. This will also help realizing easy
turning of the shoulders.
[0017] As in a second aspect of the present disclosure, the seat
device may include a seat surface on which a person is seated.
[0018] It is preferred, as in a third aspect of the present
disclosure, that the upper body support surface of the seat device
further includes lower rib horizontal ridges (or simply horizontal
ridges) which are substantially horizontal and positioned within a
range covering the tenth to the twelfth ribs.
[0019] The lower rib horizontal ridges also hinder a seated
person's tilting motion of the upper body in the horizontal
direction. Accordingly, the horizontal sway of the seated person's
posture is suppressed much more.
[0020] When the seat surface is provided, it is preferred, as in a
fourth aspect of the present disclosure, that the upper body
support surface includes a pair of ilium support projections (or
simply support projections) which are fitted to a pair of ilium
projections and that the seat surface is provided with a pair of
ischium accommodating recesses that accommodate a pair of ischium
projected portions.
[0021] Although the detailed reasons for this will be described
later, owing to the ilium support projections and the ischium
accommodating recesses, a submarining phenomenon is unlikely to be
caused. In other words, the imbalance of a seated person's posture
in the forward and rearward directions is suppressed. Also, the
posture suppressed from being imbalanced in the forward and rear
ward directions is easily retained. Thus, the seated person
recovers from fatigue earlier.
[0022] Further, the seated person can fully hold their feet on the
floor. Thus, the seat device of the present disclosure is
particularly favorable when it is used for a driver's seat of a
vehicle, in which a seated person is required to handle the brake
pedal or the accelerator pedal. The reasons why a seated person
comes to be able to fully hold the person's feet on the floor will
also be described later.
[0023] The size of pelvis depends on individual persons.
Accordingly, the positions of ischia and ilia, which are parts of
pelvis, in a seated state depend on individual persons. Therefore,
it will be most preferred to determine the positions of the ilium
support projections and the ischium accommodating recesses, on an
individual person basis.
[0024] Meanwhile, the size of pelvis is not so greatly different
between individual persons if the individual persons are adults.
Therefore, the positions of the ilium support projections and the
ischium accommodating recesses may not be required to be determined
on an individual person basis. In this case, the positions of the
ilium support projections and the ischium accommodating recesses
may be determined by limiting attributes, such as male adult or
female adult, of a seated person and considering an average pelvis
of the persons having the limited attributes. More preferably, the
size of the ilium support projections and the ischium accommodating
recesses may be determined considering a variation range of the
pelvises of the persons having the attributes.
[0025] According to a fifth aspect of the present disclosure, the
upper body support surface further includes rib support slant
ridges (or simply slant ridges) which are fitted to the ribs from
beneath when the ribs are descended in exhalation. The rib support
slant ridges are slanted along the inclination of the ribs.
[0026] Since the ribs are supported by the rib support slant
ridges, a seated person's upper body is further suppressed from
being imbalanced in the horizontal direction. In addition, this
will also provide an advantage of easing the seated person's
breathing. The reasons why the seated person's breathing is eased
will be described later.
[0027] It is preferred, as in a sixth aspect of the present
disclosure, that the rib support slant ridges are provided between
the ninth and the tenth ribs, being in contact with them.
[0028] Although the detailed reasons will be described later, such
a contact of the rib support slant ridges with the ninth and the
tenth ribs particularly enhances the advantage of easing seated
person's breathing.
[0029] It is preferred, as in a seventh aspect of the present
disclosure, that the seat surface further includes a pair of thigh
position reference ridges (or simply reference ridges) which are
each fitted to a recess between the biceps femoris muscle and the
semimembranosus muscle of the respective thigh of a seated
person.
[0030] Being provided with the thigh position reference ridges, the
thighs of a person in a seated state will stably stay in position.
Accordingly, when the upper body of the person is imbalanced in the
horizontal direction, the upper body is easily restored to the
original posture with reference to the stably positioned thighs.
Since it is important to stably retain a seated person's upper body
in position when the person drives a vehicle, the seat device of
the present disclosure is particularly favorable when it is used
for a driver's seat of a vehicle.
[0031] With a normal chair, when a seated person's lower legs are
moved, the thighs are also moved interlocking with the motion of
the lower legs. In this regard, according to the seventh aspect of
the present disclosure, the thighs are permitted to stably stay in
position. Thus, the lower legs can be moved using the knees at the
ends of the respective thighs as fulcrums. Accordingly, when the
lower legs are moved, the thighs are suppressed from being moved
interlocking with the motion of the lower legs, leading to easy
motion of the lower legs. In this way, use of the seat device for a
driver's seat of a vehicle will make it easy for the driver to
operate the accelerator pedal or the brake pedal. In this regard as
well, the seat device of the present disclosure may be particularly
favorably used for a driver's seat of a vehicle.
[0032] Further, it is preferred, as in an eighth aspect of the
present disclosure, that an upper part of the upper body support
surface including at least the shoulder blade aid ridges and
extending to the top is made vertically movable with respect to the
seat surface.
[0033] A rib position relative to the seat surface comparatively
greatly varies depending on individual persons. Therefore, when the
upper part of the upper body support surface including the shoulder
blade aid ridges is made vertically movable, the position of the
shoulder blade aid ridges may be brought to the position matching
the rib position which varies depending on individual persons.
[0034] It is preferred, as in a ninth, a tenth and an eleventh
aspects of the present disclosure, that, when the lower rib
horizontal ridges or/and the rib support slant ridges are provided
in addition to the shoulder blade aid ridges, an upper part of the
upper body support surface including these ridges and extending to
the top is made movable in the vertical direction with respect to
the seat surface.
[0035] Thus, not only the shoulder blade aid ridges but also the
lower rib horizontal ridges and the rib support slant ridges are
adjusted to a rib position that varies depending on individual
persons.
[0036] According to a twelfth aspect of the present disclosure,
substantially horizontal ridges are provided. These ridges can
function as the shoulder blade aid ridges. Thus, according to the
twelfth aspect of the present disclosure, the same advantage as
that of the eighth aspect can be obtained.
[0037] According to a thirteenth and a fourteenth aspects of the
present disclosure, slant ridges and substantially horizontal
ridges are provided. These ridges can essentially function as the
rib support slant ridges and the lower rib horizontal ridges. Thus,
according to the thirteenth and the fourteenth aspects of the
present disclosure, the same advantages as those of the ninth and
the tenth aspects, respectively, can be obtained.
[0038] According to a fifteenth aspect of the present disclosure,
the upper body support surface further includes a pair of ilium
support projections. A part of the upper body support surface
including the pair of ilium support projections is undetachably
connected to the seat surface.
[0039] An ilium position relative to the seat surface is not so
different between individual persons. Therefore, if the part of the
upper body support surface including the ilium support projections
is also moved in the vertical direction together with the part
including the shoulder blade aid ridges and the lower rib
horizontal ridges, the ilium support projections may not be fitted
to the respective ilium projections. In this regard, according to
the fifteenth aspect of the present disclosure, the part of the
upper body support surface including the ilium support projections
is undetachably connected to the seat surface. Thus, when the part
including the ridges is vertically moved, the part including the
ilium support projections will stay unmoved in the vertical
direction. Accordingly, while the positions of the ridges are
adjusted, the state where the ilium support projections are fitted
to the respective ilium projections is retained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] In the accompanying drawings:
[0041] FIG. 1 is a perspective view illustrating a seat according
to an embodiment of a seat device of the present invention;
[0042] FIG. 2 is a schematic front view illustrating a pelvis of an
adult male;
[0043] FIG. 3 is a vertical cross sectional view illustrating the
seat taken along a plane passing through a pair of ischium
accommodating recesses (i.e. taken along a line III-III of FIG.
1);
[0044] FIG. 4 is a side view illustrating the pelvis of an adult
male;
[0045] FIG. 5 is a schematic top view illustrating the pelvis of an
adult male
[0046] FIG. 6 is a cross-sectional view illustrating the seat taken
along a plane passing through the centers of a left ilium support
projection, a left ischium accommodating recess and a left thigh
position reference ridge (i.e. taken along a line VI-VI of FIG.
1);
[0047] FIG. 7 is a cross-sectional view taken along a plane passing
through a pair of ischium accommodating recesses (i.e. taken along
a line VII-VII of FIG. 1);
[0048] FIG. 8 is a schematic structural view illustrating ribs,
shoulder blades and backbones; and
[0049] FIG. 9 is an illustration conceptually explaining an
inseparable portion and a separable and movable structure of a seat
according to a modification of the present embodiment and a cover
on the seat where the present invention can also be applied on the
cover.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] With reference to the accompanying drawings, hereinafter
will be described an embodiment of a seat device for retaining
person's seated position (conceptually includes the seated position
retention device) according to the present invention.
[0051] In the embodiment, "retaining a person's seated position"
intends to mean "assisting a person to retain their seating
position."
[0052] FIG. 1 is a perspective view illustrating a seat 1 according
to an embodiment of the seat device with the seated position
retention function. The seat 1 is used as a driver's seat of a
vehicle. The seat 1 includes a seat member 10, an upper body
support member (or backrest) 20 and a headrest 30. The seat member
10, the upper body support member 20 and the headrest 30 have
surfaces made of the same material, i.e. these members are covered
with the same soft material, such as fabric or leather. The seat
member 10 serves as a member to be seated by a person. The upper
body support member 20 serves as a member for supporting the upper
body, such as the lumbar back or upper body back, of the person.
The headrest 30 serves as a member for supporting the back of the
head of the person.
[0053] In the present embodiment, horizontal, longitudinal and
vertical directions can be set to the seat 1 as illustrated in FIG.
1. The horizontal direction is a width direction along which the
seat 1 extends laterally in its front view or its rear view, the
longitudinal direction is a depth direction along which the seat 1
extends in one of its side views, and the vertical direction is a
height direction along which the seat 1 extends from a vehicle
floor, for example.
[0054] The seat member 10 has an upper surface, i.e. a seat surface
11, in which a pair of ischium accommodating recesses 40 and a pair
of thigh position reference ridges 70 are formed. FIG. 2 is a
schematic front view illustrating a pelvis 50 of an adult male. As
shown in FIG. 2, two ischia 60 in the pelvis have respective two
ischium projected portions 61. When a person is seated on the seat
surface 11, the ischium accommodating recesses 40 accommodate the
respective ischium projected portions 61 via the skin and the
flesh.
[0055] The position of the ischium accommodating recesses 40 in the
seat surface 11 is determined such that the ischium accommodating
recesses 40 are ensured to be opposed to the respective ischium
projected portions 61, when a person is seated on the seat surface
11.
[0056] Thus, the pelvis and the back of the person will be
supported by the upper body support member 20. The position of the
ischium accommodating recesses 40 in the seat surface 11 is
determined based on the size of the pelvis 50 of average
adults.
[0057] FIG. 3 is a vertical cross-sectional view illustrating the
seat member 10, taken along a plane passing between the pair of
ischium accommodating recesses 40 (i.e. taken along line III-III of
FIG. 1). As shown in FIG. 3, the ischium accommodating recesses 40
each have a shape of a bowl. Specifically, each ischium
accommodating recess 40 has a center at the deepest position
thereof toward which the recess 40 is slanted to an extent of a
shallow bowl.
[0058] As shown in FIG. 3, the ischium accommodating recesses 40
are provided so as to be symmetric with reference to a widthwise
center plane C1 of the seat member 10. The two ischium
accommodating recesses 40 have a spacing therebetween and a
widthwise length, which are determined based on the spacing and the
size of the two ischium projected portions 61 of average adults.
Also, the degree of slant and the depth as well as a longitudinal
length (perpendicular to the widthwise direction), not shown, of
each of the ischium accommodating recesses 40 are also determined
based on the size of the pair of ischium projected portions 61 of
average adults.
[0059] The spacing and the size of the two ischium projected
portions 61 of average adults here may be obtained taking into
account both or either of adult males and adult females. Whether
the adults taken into account should include both of males and
females or either of males and females may be determined based on
the usage of the seat 1. The average adults that should be taken
into account are determined in the same manner as the above, in
determining the position of the ischium accommodating recesses 40
in the seat surface 11. Also, depending on the usage, the position
of the ischium accommodating recesses 40 may be determined based on
the spacing and the size of a pair of ischium projected portions of
children. Further, the position of the ischium accommodating
recesses 40 may be determined based on the spacing and the size of
a pair of ischium projected portions of an individual person.
[0060] Referring again to FIG. 1, the configuration of the seat
surface 11 is further described. In the seat surface 11, the pair
of thigh position reference ridges 70 are formed. Also, the seat
surface 11 has sides located in the widthwise direction, both of
which are slightly uplifted.
[0061] Each thigh has, on its back, a biceps femoris muscle and a
semimembranosus muscle. There is a recess between these biceps
femoris muscle and semimembranosus muscle. In other words, there is
a portion between these biceps femoris muscle and semimembranosus
muscle, which portion more easily sinks when pushed from
immediately above these muscles than when pushed from outside. This
recess resides in approximately the center in the widthwise
direction of the back of a thigh. Since both of the biceps femoris
muscle and the semimembranosus muscle extend in the longitudinal
direction of the thigh, the recess therebetween also extends in the
longitudinal direction.
[0062] The pair of the thigh position reference ridges 70 are each
provided so as to be fitted to the recess between the biceps
femoris muscle and the semimembranosus muscle. For this reason,
specifically, the pair of thigh position reference ridges 70 are
extended from near the position where the pair of ischium
accommodating recesses 40 are formed toward a knee-side end portion
12 of the seat member 10. In this case, the two thigh position
reference ridges 70 are made parallel to each other, or,
alternatively, may be slightly distanced from each other as the
ridges 70 near the knee-side end portion 12.
[0063] Further, the height, the longitudinal length and the
widthwise length of each of the two thigh position reference ridges
70 as well as the spacing therebetween are determined such that
each of the ridges 70 is easily fitted to the recess between the
biceps femoris muscle and the semimembranosus muscle when a person
is seated on the seat surface 11. The thigh position reference
ridges 70 are each formed by placing a material beneath the
material configuring the surface of the seat 1. The material placed
beneath the material configuring the surface of the seat 1 has a
rigidity that can maintain the shape of each of the thigh position
reference ridges 70 when thighs are located on the respective
ridges 70.
[0064] Hereinafter, the configuration of the upper body support
member 20 is described. As shown in FIG. 1, the upper body support
member 20 has an upper body support surface 21 in which a pair of
ilium support projections 80 are formed at a lower portion thereof.
The two ilium support projections 80 are formed at the same level
from the seat surface 11 and have the same size and the same degree
of projection.
[0065] FIG. 4 is a side view illustrating the pelvis 50, which is
taken along a VI-VI line in FIG. 1. As shown in FIG. 4, ilia 90
configuring the upper portion of the pelvis 50 have respective
projections 91 which are projected rearward (hereinafter referred
to as "ilium projections 91"). FIG. 5 is a schematic top view
illustrating the pelvis 50 of a male adult. As shown in FIG. 5, the
ilium projections 91 are located on both sides of backbones 92, or
located sandwiching the backbones 92. In each ilium projection 91
having a projected shape, the vertical length is small but,
compared to this, the horizontal length is large. The ilium support
projections 80 provided in the upper body support member 20 are
configured to be fitted to the respective ilium projections 91 via
the skin and the flesh of a seated person. The position of the
ilium support projections 80 is determined based on the size of the
pelvis of average adults. The average adults to be taken into
account are determined in the same manner as mentioned above.
[0066] FIG. 6 is a cross-sectional view of the seat 1 taken along a
plane passing through the centers of the left ilium support
projection 80, the left ischium accommodating recess 40 and the
left thigh position reference ridge 70 (i.e. taken along a line
VI-VI of FIG. 1). FIG. 7 is a cross sectional view taken along a
plane passing through the pair of ilium support projections 80
(i.e. taken along a line VII-VII of FIG. 1). As will be understood
from FIGS. 6 and 7, the shape of each ilium support projection 80
is not a projection slanted upward, downward and leftward and
rightward centering on the peak point. Instead, the ilium support
projection 80 has the most projected portion which is approximately
linearly shaped, matching the shape of the corresponding ilium
projection 91. Also, as will be understood from FIG. 7, each ilium
support projection 80 is linearly slanted toward the widthwise
center of the upper body support surface 21. In other words, the
degree of projection of each ilium support projection 80 becomes
smaller toward the widthwise center of the upper support surface
21. Such a slant of each ilium support projection 80 also helps the
projection 80 more suitably fitted to each of the corresponding
ilium projections 91.
[0067] The position of the two ilium support projections 80
relative to the seat surface 11 and the spacing between the two
ilium support projections 80 are determined based on the spacing
and the size of the pair of ilium projections 91 of average adults.
The size of each ilium support projection 80 is determined ensuring
to support the corresponding ilium projection 91 but ensuring not
to support other portions of the upper body as much as possible. It
should be appreciated that the average adults that should be taken
into account in determining the position and the spacing of the
ilium support projections 80 are determined in the same manner as
in the case of the ischium accommodating recesses 40.
[0068] The ilium support projections 80 are each formed by placing
a material beneath the material configuring the surface of the seat
1. The material placed beneath the material configuring the surface
of the seat 1 has a rigidity that can maintain the shape of each of
the ilium support projections 80 when the respective ilium
projections 91 are supported by the ilium support projections 80.
When the brake pedal or the accelerator pedal is fully stepped on,
the depression force is large and thus the reaction force is also
large. As a result, a large force may be imposed on the ilium
support projections 80. For this reason, it is preferred that the
ilium support projections 80 have a rigidity which is able to
maintain the shape of themselves when such a large reaction force
is imposed.
[0069] The upper body support surface 21 of the upper body support
member 20 is further provided with a pair of rib support slant
ridges 100 and a pair of shoulder blade aid ridges 110 and a pair
of lower rib horizontal ridges 120.
[0070] The rib support slant ridges 100 are ensured to fit to ribs
from beneath when the ribs descend with exhalation. The "ribs that
descend with exhalation" mainly refer, here, to the ninth to the
twelfth ribs to which respective inferior posterior serratus
muscles are connected. Accordingly, the rib support slant ridges
100 are each located at a position that allows the ridge 100 to fit
to any one of the ninth to twelfth ribs from beneath. For example,
the rib support slant ridges 100, when being fitted to the
respective ninth ribs from beneath, are each positioned between the
ninth and the tenth ribs, being in contact with them
[0071] The ninth to the twelfth ribs are connected to the ribs
located at higher positions through body tissues, and thus the ribs
located higher than the ninth ribs also descend with exhalation.
Accordingly, for example, the rib support slant ridges 100 may be
positioned between the eighth and the ninth ribs, being in contact
with them.
[0072] As shown in FIG. 1, the two rib support slant ridges 100 of
the present embodiment are spaced apart from each other. The length
of the spacing is made larger than the thickness of the backbones
so that the backbones are prevented from being pressed by the rib
support slant ridges 100. Also, each one of the rib support slant
ridges 100 is slanted downward from an end portion thereof near the
other one of the rib support slant ridges 100 (backbone-side end
portion) toward the other end portion thereof (outer end portion).
The angle of this slant is ensured to substantially coincide with
the inclination angle of the ribs against which the rib support
slant ridges 100 are fitted.
[0073] The rib support slant ridges 100 each have the length,
thickness and rigidity as described below. Specifically, the length
may preferably be set to an average length of the ribs (e.g., the
ninth ribs) to be fitted to. However, the length larger or smaller
than this may also allow the rib support slant ridges 100 to exert
the effects thereof. The thickness is ensured to be smaller than
the distance between the pair of ribs to be fitted to and the pair
of ribs located immediately beneath the pair of ribs to be fitted
to, but to be large enough to support the pair of ribs to be fitted
to. For example, the thickness may be approximately the same as the
thickness of the pair of ribs to be fitted to. The rigidity is set
to a level that will not allow a seated person to be hurt when the
person leans back to the upper body support member 20, but will
allow the rib support slant ridges 100 to adequately support the
ribs.
[0074] In a person's seated state, the position of the person's
ribs relative to the seat surface 11 may comparatively greatly
differ, depending on the persons seated. For this reason, the
position of the person's ribs relative to the seat surface 11 is
determined based on an average body size. Nevertheless, depending
on the persons seated, the position of the rib support slant ridges
100 may not match the position of the person's ninth ribs to be
fitted to from beneath.
[0075] However, as mentioned above, the rib support slant ridges
100 do not have to be necessarily fitted to the ninth ribs but may
be fitted to the tenth or the eleventh ribs, or alternatively, may
be fitted to the eighth ribs. In addition, the inclination angles
of these ribs do no greatly differ from each other. Accordingly,
although the position of the rib support slant ridges 100 relative
to the seat surface 11 is fixed in the present embodiment, a person
of any seating height may be seated on the seat 1 to have the rib
support slant ridges 100 fitted to the person's descending ribs
from beneath in exhalation.
[0076] The pair of shoulder blade aid ridges 110 are positioned
within a vertical range covering the fifth to the seventh ribs of a
seated person. Accordingly, as shown in FIG. 1, the shoulder blade
aid ridges 110 are located above the rib support slant ridges 100.
The two shoulder blade aid ridges 110, each being substantially
horizontal, are juxtaposed in the horizontal direction. The
"substantially horizontal" here refers to that these ridges 110 are
slanted to an extent of the inclination angles of the fifth to the
seventh ribs in the state where the backbones of the seated person
are upright.
[0077] Referring to FIG. 8, the shoulder blade aid ridges 110 are
specifically described. FIG. 8 is a schematic structural view
illustrating ribs, shoulder blades and backbones.
[0078] Each of the shoulder blade aid ridges 110 has a
backbone-side end portion which is ensured to be positioned between
a backbone-side end of the corresponding shoulder blade and the
backbones. The length from a widthwise center line C2 (see FIG. 1)
of the upper body support surface 21 to the backbone-side end
portion of each shoulder blade aid ridge 110 is figured out as
follows. Specifically, this length is equal to or larger than a
horizontal length dl from a backbone center line C2' to a backbone
end, which corresponds to half the thickness of each backbone (see
FIG. 8), but equal to or smaller than a horizontal length d2 from
the backbone center line C2' to an outer end of a part of the
corresponding shoulder blade, which falls within the range of from
the fifth to the seventh ribs (see FIG. 8).
[0079] However, since shoulder blades are capable of various
motions, the length d2 changes with the motion of each of the
shoulder blades. Therefore, the length d2 that should be taken into
account is rendered to be the minimum length d2 in the turning
motion of the shoulder blades.
[0080] As mentioned above, in a person's seated state, the rib
position of the person relative to the seat surface 11 may
comparatively greatly differ, depending on the persons seated. For
this reason, the rib position of the person relative to the seat
surface 11 is determined based on an average body size. Also, the
longitudinal length of each of the shoulder blade aid ridges 110 is
not particularly limited if only the shoulder blade aid ridges 110
can be formed in the upper body support surface 21. For example,
each of the shoulder blade aid ridges 110 may have a longitudinal
length corresponding to approximately half the widthwise length of
the back of a person of an average size.
[0081] The vertical position of the pair of lower rib horizontal
ridges 120 is determined taking into account a seating height of
average persons. Specifically, the lower rib horizontal ridges 120
are formed within a vertical range covering the tenth to the
twelfth ribs which are located at the lowest in all of the ribs.
Accordingly, as shown in FIG. 1, the lower rib horizontal ridges
120 are positioned below the rib support slant ridges 100 and above
the ilium support projections 80.
[0082] The two lower rib horizontal ridges 120, each being
substantially horizontal, are juxtaposed in the horizontal
direction. The "substantially horizontal" here refers to that these
ridges 120 are slanted to an extent of the inclination angles of
the tenth to the twelfth ribs in the state where the backbones of
the seated person are upright. The horizontal position and the
length of the pair of lower rib horizontal ridges 120 are not
particularly limited. However, it is preferable that the lower rib
horizontal ridges 120 are provided so as not to be in contact with
the backbones. To this end, the lower rib horizontal ridges 120 of
the present embodiment each have a backbone-side end portion which
is ensured to be distanced from the widthwise center line C2 of the
upper body support surface 21 by the length dl (see FIG. 8) or
more. In the present embodiment, each of the rib support slant
ridges 100, each of the shoulder blade aid ridges 110 and each of
the lower rib horizontal ridges 120 have respective lengths and
positions, which are determined so that these ridges, 100, 110 and
120 each have the same lengths L1 and L2 from the widthwise center
line C2 to the backbone-side end portion and to the outer end
portion, as shown in FIG. 7.
[0083] In the upper body support surface 21 of the present
embodiment, the portions F out of the outer end portions of the
ridges 100, 110 and 120 are curved so as to be projected forward,
as shown in FIG. 7. Thus, the upper body of a seated person is
unlikely to be imbalanced in the horizontal direction.
[0084] Hereinafter will be described the advantages obtained from
the seat 1 configured as described above with a person being
seated. First, an advantage of facilitating retention of a seated
person's posture is described.
[0085] The structure most related to this advantage is the pair of
ilium support projections 80 and the pair of ischium accommodating
recesses 40. The pair of ilium support projections 80 formed in the
seat 1 support the pair of ilium projections 91 of a seated person.
In other words, it is ensured that a force is applied to the pair
of ilium projections 91 of a seated person from the pair of ilium
support projections 80. Since the ilium projections 91 are located
in an upper part of the pelvis, the application of a force to the
ilium projections 91 means that the force is applied to the pelvis
such that the person is allowed to lean forward. Thus, a
submarining phenomenon in which a seated person's pelvis leans
rearward is unlikely to be caused.
[0086] In a state where a seated person's pelvis does not lean
rearward, the person's pair of ischium projected portions 61 are
accommodated in the pair of ischium accommodating recesses 40
formed in the seat surface 11. Also, in a state where a seated
person's pelvis does not lean rearward, the upper body is
approximately upright, allowing the upper body to push the ischia
with a large force. Therefore, a state where the ischia are
accommodated in the respective ischium accommodating recesses 40
can be easily retained. For these reasons, a submarining phenomenon
is unlikely to be caused and the seated person's upright posture is
easily retained. In addition, since the seated person's upright
posture is easily retained, the person will recover from fatigue
quickly.
[0087] Further, when a seated person holds the person's feet on the
floor as well, the reaction force transferring from the soles to
the trunk is received by the ilium support projections 80 of the
seat 1 via the person's ilium projections 91. The ilium support
projections 80 are projected out of the area where they are
provided. Accordingly, the reaction force mentioned above is mainly
received by the ilium support projections 80, reducing the rate
that the reaction force is received by portions other than the
ilium support projections 80.
[0088] Specifically, the rate of reaction force received by the
upper body support surface 21 via backbones and lumbar becomes
small. Thus, the load that will be imposed on the backbones and
lumbar is mitigated. Also, human's ilium projections 91 do not feel
so much pain when a large force is applied from outside. For these
reasons, compared to normal chairs that allow an upper body to be
mainly supported by backbones and lumbar, the load imposed on a
seated person's body is reduced even when the person fully holds
the person's feet on the floor.
[0089] Thus, a seated person also can fully step on an accelerator
pedal or a brake pedal.
[0090] Thus, with the seat 1 of the present embodiment, a seated
person's posture is easily retained by the ischium accommodating
recesses 40 and the ilium support projections 80. In addition to
this, with the seat 1 of the present embodiment, the horizontal
motion of the person's upper body is suppressed by the rib support
slant ridges 100, the shoulder blade aid ridges 110 and the lower
rib horizontal ridges 120 provided in the upper body support
surface 21. Thus, these ridges 110, 110 and 120 also contribute to
easy retention of the posture of the seated person. Further, the
thigh position reference ridges 70 provided in the seat surface 11
determine the positions of the thighs. This will also help easily
retaining the posture of the seated person.
[0091] Hereinafter is described an advantage of easing seated
person's breathing. The structure most related to this advantage is
the rib support slant ridges 100.
[0092] There are various body tissues between ribs, which establish
connection between ribs. Accordingly, if the rib support slant
ridges 100 are not provided, muscles (e.g. inferior posterior
serratus muscle) that contract in exhalation not only allow the
ribs, to which the muscles are connected, to descend, but also
allow upper ribs, to which the muscles are not connected, to
descend.
[0093] In this regard, the seat 1 of the present embodiment is
provided with the rib support slant ridges 100. These rib support
slant ridges 100 are fitted to seated person's ribs from beneath,
which descend in exhalation. Thus, upper ribs located around the
chest are suppressed from descending, so that the chest is likely
to be kept open. Accordingly, the seated person can breathe with
ease.
[0094] In particular, the rib support slant ridges 100, when
positioned between the ninth and the tenth ribs, will exert a large
effect of easing the seated person's breathing. The reason for this
is as follows. Specifically, the tenth and lower ribs are included
in an abdominal muscle system to which the abdominal muscles are
connected, and thus descend with the contraction of the abdominal
muscles.
[0095] On the other hand, the ninth and upper ribs are not
connected to the abdominal muscles but to inspiratory muscles.
Therefore, when the rib support slant ridges 100 are positioned
between the ninth and the tenth ribs, these ribs are efficiently
suppressed from being lowered by the muscles in the abdominal
muscle system, while the motion of the inspiratory muscles is not
hindered. In this way, the advantage of easing the person's
breathing is enhanced.
[0096] As described above, owing to the configuration such as of
the ilium support projections 80 and the pair of ischium
accommodating recesses 40, a seated person's posture is easily
retained. In the posture retained such as by the ilium support
projections 80 and the pair of ischium accommodating recesses 40,
the person will receive less pressure on the chest. Accordingly,
the configuration such as of the ilium support projections 80 and
the pair of ischium accommodating recesses 40 also enhances the
advantage of easing the person's breathing.
[0097] Hereinafter is described an advantage that a seated person's
posture is easily restored to the original posture. The structure
most related to this advantage is the thigh position reference
ridges 70. The thigh position reference ridges 70 are each provided
so as to fit into a recess between the seated person's biceps
femoris muscle and the semimembranosus muscle. When each thigh
position reference ridge 70 is fitted to the recess between the
biceps femoris muscle and the semimembranosus muscle, the position
of the corresponding thigh is determined. With a normal chair,
horizontal sway of a seated person's upper body usually allows the
thighs to also move interlocking with the horizontal sway. However,
in the present embodiment, the thigh position reference ridges 70
determine the positions of the respective thighs and the thighs
stably stay at the positions.
[0098] Accordingly, when the upper body is imbalanced in the
horizontal direction as well, the thighs are suppressed from moving
in the horizontal direction interlocking with the horizontal
imbalance of the upper body. Thus, the positions of the respective
thighs serve as references. Accordingly, when the upper body is
horizontally imbalanced, the upper body can be easily restored to
the adequate original posture with reference to the stably
positioned thighs. The adequately postured upper body will help
reduce muscle fatigue of the seated person, and the person is
unlikely to get tired. In addition, in order to drive a car safely,
it is important to stably keep the upper body in position, and thus
the seat 1 of the present embodiment is useful for safe
driving.
[0099] Hereinafter is described an advantage that lower legs are
allowed to be easily moved. The structure most related to this
advantage is again the thigh position reference ridges 70.
[0100] With a normal chair, when lower legs are moved, the thighs
are also moved interlocking with the motion of the lower legs.
However, in the present embodiment, the thigh position reference
ridges 70 determine the positions of the respective thighs and the
thighs will stably stay in position.
[0101] Thus, when the lower legs are moved, the knees at the ends
of the respective thighs serve as fulcrums. Specifically, when the
lower legs are moved, the thighs are suppressed from moving
interlocking with the motion of the lower legs, while only the
lower legs are allowed to move. Thus, the lower legs are easily
moved. Accordingly, the accelerator pedal or the brake pedal is
easily operated. With the easy operation of the pedals, fatigue
caused during driving is mitigated. It should be appreciated that
the advantage of easily retaining a seated person's posture will
also help mitigating fatigue caused during driving.
[0102] Hereinafter is described an advantage that horizontal
imbalance of a seated person's posture is suppressed. The
structures most related to this advantage are the shoulder blade
aid ridges 110 and the lower rib horizontal ridges 120.
[0103] The shoulder blade aid ridges 110, being substantially
horizontal, substantially hinder the tilting motion of a seated
person's upper body in the horizontal direction. As a result,
horizontal imbalance of the upper body is suppressed.
[0104] On the other hand, a rotational motion of the upper body
centering the backbones will not be hindered by the shoulder blade
aid ridges 110. Accordingly, when the seated person looks left or
right, the horizontal sway of the upper body is suppressed, while
the rotational motion of the upper body for turning the person's
face to the left or right is accelerated. As a result, undesirable
horizontal sway of the head during driving is suppressed.
[0105] The lower rib horizontal ridges 120 are substantially
horizontal within a range covering the tenth to the twelfth ribs
which are connected to the abdominal muscles. Thus, the motion of a
seated person's abdominal muscles, which is guided by the lower rib
horizontal ridges 120, becomes easier. This motion corresponds to
the rotation of the lumbar. The rotation of the lumbar in other
words is the rotational motion of the upper body centering the
backbones. Therefore, resultantly, the horizontal sway of the upper
body is also suppressed by the lower rib horizontal ridges 120. In
order that the above advantage is obtained by the lower rib
horizontal ridges 120, it is most favorable that the lower rib
horizontal ridges 120 are brought into contact with the lower ends
of the pair of tenth ribs.
[0106] Hereinafter is described an advantage that seated person's
shoulders are rotated with ease. The structure most related to this
advantage is again the shoulder blade aid ridges 110. When a person
is seated on the seat 1, a backbone-side end portion of each of the
shoulder blade aid ridges 110 is positioned between the backbones
and a backbone-side end portion of the corresponding shoulder
blade. Therefore, the backbone-side end portion of the shoulder
blade aid ridge 110 is used as a fulcrum of turn, and thus the
turning of the corresponding shoulder blade is aided. Thus, the
motion of the shoulders accompanying turning of the shoulder blades
becomes easier. In this way, when the person is seated on a
driver's seat, handling of the steering wheel becomes easier.
[0107] Shoulder blades are pulled downward by lower trapezius
muscles. Meanwhile, shoulder blades are supported by the respective
shoulder blade aid ridges 110. Therefore, the shoulder blades are
suppressed from being lowered. This will also help realizing easy
turning of the shoulders.
[0108] The present invention is not limited to the embodiment
described so far. The following modifications may also fall within
the technical range of the present invention. Further, the present
invention may also be modified and implemented in various other
ways within a range not departing from the spirit of the
invention.
[0109] For example, although only a pair of rib support slant
ridges 100 have been provided in the above embodiment, two or more
pairs may be provided. For example, a first pair of rib support
slant ridges may be provided between the ninth and the tenth ribs
being in contact with them, and a second pair of rib support slant
ridges may be provided between the tenth and the eleventh ribs
being in contact with them. Thus, the ribs are further suppressed
from being lowered, whereby a seated person's breathing is more
eased.
[0110] In the embodiment described above, the rib support slant
ridges 100, the shoulder blade aid ridges 110 and the lower rib
horizontal ridges 120 have been fixed to the upper support surface
21 (i.e, the seat member 10 in the embodiment), or in other words,
the positions of these ridges have been unchangeable in the
vertical direction. However, positions of the objects to be
supported, i.e. a rib position and a shoulder blade position,
relative to the seat surface 11 are different comparatively greatly
depending on the persons seated. On the other hand, position of the
ilium projections 91 relative to the seat surface 11 is
comparatively less different between persons seated. The ilium
projections 91 are supported by the respective ilium support
projections 80 which are also formed in the upper body support
surface 21.
[0111] Considering this, the seat 1 may be configured as follows.
Specifically, as pictorially shown in FIG. 9, the upper body
support member 20 may be separated into a part that includes the
ilium support ridges 80 (hereinafter referred to as " lower
upper-body support LP") and a part that includes at least one of
the rib support slant ridges 100, the shoulder blade aid ridges 110
and the lower rib horizontal ridges 120 (hereinafter referred to as
"upper upper-body support UP"). The lower upper-body support LP may
be undetachably connected to the seat surface 11 (i.e., the seat
member 10 in the embodiment) and the upper upper-body support UP
may be made vertically movable with respect to the seat surface 11.
In this case, the upper upper-body support UP is ensured to have a
movable range including a variation range of the positions of the
object ribs for the ridges 100, 110 and 120, relative to the seat
surface 11, which may vary depending on persons seated.
[0112] A specific configuration is given here for the vertical
movement of the upper upper-body support UP relative to the seat
surface 11. For example, as conceptually shown in an enlarged part
A of FIG. 9, a plurality of metal poles PL may be used for
connecting the upper upper-body support UP and the lower upper-body
support LP, in a similar manner to the connection between the upper
body support 20 and the headrest 30.
[0113] In the upper body support surface 21, the part included in
the upper upper-body support UP corresponds to the "upper part of
the upper body support surface", while the part included in the
lower upper-body support LP corresponds to the "lower part of the
upper body support surface".
[0114] The above embodiment has been described taking as an example
the seat 1. However, the present embodiment may be applied to
chairs having legs. Such chairs having legs are usually used in a
house and a variety of such chairs are available, with the
materials of the seat surfaces and upper body support surfaces
being wood, vinyl and the like.
[0115] When the present invention is applied to such chairs as
well, there is no particular limitation in the materials of the
seat surfaces and the upper body support surfaces, and thus various
materials similar to those of the chairs of conventional art may be
used.
[0116] The present invention may be applied to covers CV for chairs
and seats (refer to FIG. 9). The covers CV correspond to the seated
position retention device to which the present invention can also
be applied. When the present invention is applied to the covers CV
as well, the upper upper-body support UP and the lower upper-body
support LP may be separately provided. In this case, the lower
upper-body support LP may be undetachably connected to the seat
member and the upper upper-body support UP may be made vertically
movable with respect to the seat member.
[0117] When the present invention is applied to the covers CV, a
cover for the upper body support surface may not be provided but
only a cover for the seat surface may be provided. Alternatively, a
cover for the seat surface may not be provided but only a cover for
the upper body support surface may be provided.
[0118] Though already stated in the foregoing, the
three-dimensional sizes and positions (including slant angles) of
the thigh position reference ridges 70, the ilium support
projections 80, the lower rib horizontal ridges 120, the support
slant ridges 100 and the shoulder blade aid ridges 110 can be
provided as order-made products or ready-made products on the seat
device or the cover. In the order-made product, the body sizes of
each person who use the product are reflected in the sizes and
positions of those ridges. In contrast, in the read-made products,
the statistically acquired standard body sizes or statistically
acquired, but categorized into a plurality of typical sizes (large,
medium or small, for example) of persons are reflected in the sizes
and positions of the ridges. In this respect, the sizes and
positions of the ridges can be determined uniquely as a matter of
fact.
* * * * *