U.S. patent application number 14/896236 was filed with the patent office on 2016-05-19 for chair.
The applicant listed for this patent is ITOKI CORPORATION. Invention is credited to Eric CHAN, Seitaro KOMOTO.
Application Number | 20160135603 14/896236 |
Document ID | / |
Family ID | 52008259 |
Filed Date | 2016-05-19 |
United States Patent
Application |
20160135603 |
Kind Code |
A1 |
CHAN; Eric ; et al. |
May 19, 2016 |
CHAIR
Abstract
A chair includes a seat, a backrest and a back frame having a
rigid structure and arranged behind the backrest with an interval
in between. The backrest is attached to the back frame by a first
support device arranged at a height position close to an upper end
of the backrest and by a second support device arranged at a
position lower than the first support device and higher than a seat
surface. The first support device is attached to a part close to a
right-left middle part of the upper end part in the backrest. The
second support device is attached to a left end part and a right
end part of the backrest.
Inventors: |
CHAN; Eric; (New York,
NY) ; KOMOTO; Seitaro; (Osaka-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ITOKI CORPORATION |
Osaka-shi, Osaka |
|
JP |
|
|
Family ID: |
52008259 |
Appl. No.: |
14/896236 |
Filed: |
June 6, 2014 |
PCT Filed: |
June 6, 2014 |
PCT NO: |
PCT/JP2014/065094 |
371 Date: |
December 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61831763 |
Jun 6, 2013 |
|
|
|
Current U.S.
Class: |
297/284.7 ;
297/285; 297/440.2 |
Current CPC
Class: |
A47C 7/40 20130101; A47C
7/46 20130101; A47C 7/36 20130101; A47C 7/462 20130101; A47C 7/44
20130101 |
International
Class: |
A47C 7/44 20060101
A47C007/44; A47C 7/46 20060101 A47C007/46; A47C 7/36 20060101
A47C007/36 |
Claims
1. A chair comprising: a seat; a backrest; and a back frame having
a rigid structure and arranged behind the backrest with an interval
in between, wherein the backrest is attached to the back frame by a
first support device arranged at a height position close to an
upper end of the backrest and by a second support device arranged
at a position lower than the first support device and higher than a
seat surface, the first support device is attached to a part close
to a right-left middle part of the upper end part in the backrest,
and the second support device is attached to a left end part and a
right end part of the backrest.
2. The chair according to claim 1, wherein the first support device
has such an elastic strength that, when a body pressure of a seat
occupant acts on the backrest, permits warp deformation and thereby
allows an upper part of the backrest to move and deviate rearward,
whereas the second support device has such a rigidity that, even
when a body pressure of a seat occupant acts, bending deformation
does not substantially occur or, alternatively, although elastic
deformation is caused by the body pressure of the seat occupant,
the second support device has the elastic strength with which a
magnitude of the elastic deformation of the second support device
is lower than that of the first support device.
3. The chair according to claim 1, wherein the first support device
is in an attitude elongated in up and down directions in side view,
whereas the second support device is separated into two right and
left parts and then the right and left second support devices are
in such an inclined attitude that an interval of the right and left
second support devices becomes wider as going to a nearer side in
plan view.
4. The chair according to claim 1, wherein the back frame includes
a pair of right and left vertically elongated members, these right
and left vertically elongated members being inclined such that an
interval becomes narrow as going upward, and upper ends being
connected integrally through a linkage part, and the first support
device is attached to the linkage part of the back frame and the
second support device is attached to the right and left vertically
elongated members.
5. The chair according to claim 1, wherein the backrest includes a
main member fabricated from resin and attached to the back frame,
the main member includes a framework having a loop shape and
constituting an outer periphery and a body support part located in
an inner side thereof, and the body support part is provided with a
large number of slits or holes so as to have such a strength that
deformation is easily caused by a body pressure of a seat
occupant.
6. The chair according to claim 5, wherein a cushion is arranged in
a front face of the main member and at least the cushion is covered
by a skin material.
7. The chair according to claim 5, wherein a lower end of the main
member is located close to the seat surface, a lumbar support
member for supporting a lumbar portion of a seat occupant is
arranged on the front face or the rear face of the main member and,
further, the main member is attached to the second support device
at a position slightly higher than the lumbar support member.
8. The chair according to claim 1, wherein when a body pressure of
a seat occupant acts, the backrest is inclined rearward.
9-17. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention relates to a chair and, in particular,
treats an office-use chair as a preferred object.
BACKGROUND ART
[0002] The first factor to be owned by a chair is comfort to a
user. In particular, in a chair used in an office, a person
continues sitting down for a long time and hence comfort is an
important factor. There are some factors damaging comfort.
Typically, such factors include a feeling of oppression caused by a
situation that the portion hitting the body is hard and a feeling
of tightness that the body cannot easily be moved. Thus,
countermeasures are taken in order to reduce the feeling of
oppression and the feeling of tightness.
[0003] The problem of the feeling of oppression is handled such
that a cushion is arranged in the seat or the backrest, the seat or
the backrest is constructed from a mesh, or the like. Adoption of a
deformable structure in the seat plate or the backrest plate is
also effective in improving softness.
[0004] On the other hand, in order that the feeling of tightness
may be prevented or reduced, it is sufficient that the movement of
the body in a state of sitting down is permitted. Imparting a
rocking function to the chair is effective means for alleviating
the feeling of tightness. Nevertheless, a simple rocking function
alone has merely a limited effect in improving comfort. This is
because a person takes various attitudes in a state of sitting down
and hence the simple rocking function cannot follow the changes in
the attitude of the person.
[0005] For example, it is usual that a seat occupant twists the
body so as to turn aside. Nevertheless, in a case that the backrest
has a rigid structure, when the person twists the body, the contact
area with the backrest decreases so that the user receives a
feeling of oppression and hence comfort is degraded.
[0006] Thus, designs have been performed for improving the
follow-up property of the backrest for the movement of the body. As
examples of these, as a structure that the backrest can be deformed
by the body pressure of a seat occupant, Documents 1 to 4 describes
a configuration that a backrest is supported by the back frame at
three positions consisting of two right and left positions in the
upper end part and of the right-left middle part of the lower end
part.
[0007] In a case that the backrest is freely deformed by the body
pressure of the seat occupant, the stability of the body is
degraded and hence comfort is degraded on the contrary. That is,
the backrest is required to have a function of firmly supporting
the body. In particular, in a case that a person sits on the chair
and performs various kinds of desk work, when the person slouches,
the internal organs are pressed and hence an intense stress acts on
the body. Thus, a high necessity is concluded that even in a
non-rocking state, the body (especially, the lumbar) of the person
is supported and held in a state that the back is straightened.
[0008] When the individual publicly known documents are viewed from
the perspective of such a function of stably supporting the body,
the backrest of the individual publicly known documents is
supported at three positions consisting of two right and left
positions at the upper end and of the right-left middle part of the
lower end part. Thus, it is concluded that excessive deformation is
avoided. Nevertheless, since the lower part of the backrest is
easily deformed, a high function of firmly supporting the body in a
non-rocking state and holding a state that the back is straightened
is not expected. That is, in the individual publicly known
documents, there is the possibility of an insufficient function of
stably supporting the body in a non-rocking state.
[0009] Further, as a use mode of a chair, it is usual that in a
rocking state, the body is twisted right or left or, alternatively,
the shoulder is deviated right or left. In this case, the load is
concentrated on the left side or the right side of the upper part
of the backrest. Nevertheless, in the individual publicly known
documents, the upper part of the backrest cannot easily be
deformed. Thus, a high follow-up property for the attitude change
of the body is not expected and hence, also in this perspective,
there is room for improvement of comfort.
[0010] Further, in many cases, the backrest of a chair is provided
with a back plate fabricated from resin. Then, as means for
alleviating the feeling of oppression and improving the cushioning
property and the fit property, a configuration is employed that the
back plate has a flexible structure. For example, in Document 5,
the applicant of the present application has disclosed that a large
number of elongated grooves horizontally elongated in the right and
left directions are provided in the back plate so that the body
support part is constructed from the multi-stage band plate group.
In this Document 5, in each band plate, in order that deformation
may easily occur, a thin trimming groove is provided in the right
and left end parts.
[0011] On the other hand, Document 6 discloses a back plate having
a configuration similar to a honeycomb structure. Further, Document
7 discloses a backrest in which cross-shaped holes and
straight-line-shaped holes are arranged regularly so that a
structure similar to a mesh is formed.
[0012] In Documents 6 and 7, the body support part of the backrest
is formed in a mesh structure. Then, a group of thin lines
constituting the body support part are individually bent and hence
the thin lines are allowed to perform extensional deformation in
accordance with the body pressure. Thus, the entire body support
part can be deformed such as to become concave rearward.
[0013] Here, the function of supporting the body achieved by the
backrest is considered below. A high flexibility alone is not
sufficient and the function of stably supporting the body is also
important. For example, when there is a tendency that the body
shakes in a rocking state, in some cases, comfort is degraded on
the contrary.
[0014] Further, in a case that the seat occupant performs desk work
like PC operation in a non-rocking state, when the lumbar is firmly
supported, an appropriate attitude in which the back is
straightened is maintained and hence this situation is preferable.
In contrast, when the flexibility of the backrest is excessively
high, the body cannot stably be supported.
[0015] Then, in Documents 6 and 7, a kind of mesh structure is
employed and hence this structure is easily deformed in the
entirety. Thus, although a high cushioning property is obtained,
room for improvement in stably supporting the body is concluded. On
the other hand, the band plate of Document 5 does not excessively
perform extensional deformation and hence excels in the stability
of supporting the body. Nevertheless, since there is a limit in the
elongation of each band plate, room for improvement in the
perspective of flexibility is concluded.
CITATION LIST
Patent Literature
[0016] Patent Document 1: JP-A-2002-119366
[0017] Patent Document 2: JP-A-2004-129966
[0018] Patent Document 3: JP-A-2010-063831
[0019] Patent Document 4: U.S. Pat. No. 7,249,802
[0020] Patent Document 5: JP-A-2011-041615
[0021] Patent Document 6: Japanese Patent No. 4015673
[0022] Patent Document 7: U.S. Pat. No. 5,934,758
SUMMARY OF THE INVENTION
Technical Problem
[0023] The invention of the present application has been devised in
view of such present situations and is intended to provide a chair
in which value in use has been enhanced and improvement has been
achieved. Further, the present application includes a large number
of improved configurations and hence to provide these may be an
object.
[0024] Further, the invention of the present application has been
devised in view of such present situations. An object thereof is to
provide a more improved backrest.
Solution to Problem
[0025] The present application is constructed from a group of
inventions having hierarchical and areal broadening. Then, typical
modes thereof are identified as a first to a fifteenth
invention.
[First Invention]
[0026] Among these, the first invention constitutes a generic
concept. The basic configuration thereof includes: a seat; a
backrest; and a back frame having a rigid structure and arranged
behind the backrest with an interval in between. Then, the backrest
is attached to the back frame by a first support device arranged at
a height position close to an upper end of the backrest and by a
second support device arranged at a position lower than the first
support device and higher than the seat surface. Further, the first
support device is attached to a part close to a right-left middle
part of the upper end part in the backrest.
[0027] Here, it is sufficient that the first support device is
attached to the upper end of the backrest or a vicinity thereof.
Thus, the backrest may run off over the first support device. That
is, the attaching position of the first support device has a
vertical width. The second support device is similar.
[0028] In the present invention, so to speak, the backrest is
supported at three positions consisting of the right-left middle
part of the upper end part and of two right and left positions
thereunder. Then, in a case that the user sits down in a state of
not leaning on the backrest in order to perform desk work like PC
operation, the lumbar and the like can stably be supported by the
portion supported at the two right and left positions within the
backrest. Thus, the state that the back is straightened can
appropriately be maintained and hence the user is allowed to take
an appropriate working attitude.
[0029] On the other hand, the first support device is close to the
right-left middle part of the backrest and hence the upper end part
(or the upper part) of the backrest runs off to the outside in the
right and left directions of the first support device so as to
constitute free ends. That is, both right and left ends of the
upper end part (the upper part) of the backrest serve as free ends
not supported from the rear. Thus, when a configuration is employed
that the upper part of the backrest can be deformed by the body
pressure, the backrest can be deformed such as to follow the twist
of the body in a state of leaning on the backrest. This contributes
to improvement in comfort in a leaning-on state.
[Second Invention]
[0030] The second invention is an example of expansion of the first
invention. In this invention, the first support device has such an
elastic strength that, when the body pressure of a seat occupant
acts on the backrest, permits warp deformation and thereby allows
an upper part of the backrest to move and deviate rearward, whereas
the second support device has such a rigidity that, even when the
body pressure of a seat occupant acts, bending deformation does not
substantially occur or, alternatively, although elastic deformation
is caused by the body pressure of the seat occupant, the second
support device has the elastic strength with which a magnitude of
the elastic deformation of the second device is lower than that of
the first support device.
[0031] In this second invention, the first support device has a
spring property. Thus, in a state that a person leans on the
backrest, the upper part of the backrest is allowed to move such as
to approach the back frame. That is, a reaction force of the first
support device acts on the upper part of the backrest from the rear
and then this reaction force provides a cushion effect and, hence,
comfort to the user. Further, the deformation in the first support
device permits twist deformation in the backrest and hence also
improves follow-up deformability in a case that the body is twisted
in the right or left direction in a state that the person leans on
the backrest.
[0032] Further, the second support device is hardly deformed by the
body pressure of a seat occupant or, alternatively, even in a case
that deformation occurs, the magnitude thereof is smaller than that
in the first support device. Thus, the function of supporting the
body in a leaning-on state is appropriately achieved. Further, when
the lower part of the backrest is excessively deformed in a
leaning-on state such as a rocking state, the stability of the body
is degraded so that, in some cases, comfort is degraded on the
contrary. However, in the second invention, even in a leaning-on
state, the body is stably supported by the lower part of the
backrest and hence excessive movement of the body is prevented so
that comfort can be improved.
[Third Invention]
[0033] The third invention is an example of expansion of the first
invention or the second invention. In this invention, the first
support device is in an attitude elongated in up and down
directions in side view, whereas the second support device is
separated into two right and left parts and then the right and left
second support devices are in such an inclined attitude that an
interval of the right and left second support devices becomes wider
as going to a nearer side in plan view.
[0034] In the present invention, the first support device and the
second support device may employ various modes. However, when the
third invention is employed, in both of the first support device
and the second support device, the portion extending between the
back frame and the backrest may be in a simple plate-shape
configuration. This provides an advantage of simplified structure.
Further, the first support device 12 is elongated in the up and
down directions and hence can easily be deformed and bent rearward
by the body pressure of a seat occupant. Thus, the follow-up
property and the cushioning property against a change of the body
can be improved.
[Fourth Invention]
[0035] The fourth invention is an example of expansion of the first
invention or the second invention. In this invention, the back
frame includes a pair of right and left vertically elongated
members, these right and left vertically elongated members being
inclined such that an interval becomes narrow as going upward, and
upper ends being connected integrally through a linkage part, and
the first support device is attached to the linkage part of the
back frame and the second support device is attached to the right
and left vertically elongated members. Here, the matter specific to
the fourth invention may be applied also to the third
invention.
[0036] For example, the back frame may be constructed from one
member located in the right-left middle part of the backrest or,
alternatively, may employ a configuration of inverted U-shape
having a right and a left vertical part. However, when the
configuration (the configuration of inverted V-shape) of the fourth
invention is employed, an advantage is obtained that a high
strength can be ensured by employing a simple configuration.
[Fifth Invention]
[0037] The fifth invention is an example of expansion of the first
invention or the second invention. In this invention, the backrest
includes a main member fabricated from resin and attached to the
back frame, the main member includes a framework having a loop
shape and constituting an outer periphery and a body support part
located in an inner side thereof, and the body support part is
provided with a large number of slits or holes so as to have such a
strength that deformation is easily caused by the body pressure of
a seat occupant. Here, the matter specific to the fifth invention
may be applied also to the third invention or the fourth invention.
The backrest may employ various configurations. However, in the
fifth invention, the main member is composed of an integrally
molded article. Thus, in comparison with a configuration that the
framework and the body support part are constructed as separated
members, the time and effort in manufacturing can be saved and
variation in the quality can also be prevented.
[0038] Here, in the fifth invention, the body support part is
provided at constant to the framework. However, as described above,
a configuration may also be employed that the body support part is
constructed from a flexible raw material such as a mesh material
and then the flexible raw material is attached to the framework. In
either case, it is preferable that the framework performs warp
deformation in accordance with the body pressure of a seat
occupant.
[Sixth Invention]
[0039] In the fifth invention, the backrest may be constructed from
the main member alone and then the body pressure of the seat
occupant may be received directly by the main member. In contrast,
in the sixth invention serving as an example of expansion of the
fifth invention, a cushion is arranged in the front face of the
main member and then at least the cushion is covered by a skin
material. In this configuration of the fifth invention, softness to
the body can be ensured by the cushion.
[Seventh Invention]
[0040] The seventh invention also is an example of expansion of the
fifth invention. In this invention, a lower end of the main member
is located close to the seat surface, a lumbar support member for
supporting the lumbar of a seat occupant is arranged on the front
face or the rear face of the main member and, further, the main
member is attached to the second support device at a position
slightly higher than the lumbar support member. Here, the matter
specific to the seventh invention may be applied also to the first
to the fourth invention or the sixth invention.
[0041] When the lumbar support member is provided like in the
seventh invention, the lumbar of the seat occupant can
appropriately be supported. Thus, this can contribute to
maintaining of an appropriate attitude by the seat occupant. Then,
since the first support device is attached to the main member on
the lumbar support member, this can avoid a situation that the
width in the right and left directions of the main member becomes
excessively large. Further, since the attaching part of the second
support device and the attaching part of the lumbar support member
are close to each other, the rigidity of the portion of the
attaching part of the lumbar support member within the main member
can also be improved and hence this can contribute to the further
stability of the body of the user.
[Eighth Invention]
[0042] The eighth invention is an example of expansion of the first
invention or the second invention. In this invention, when the body
pressure of a seat occupant acts, the backrest is inclined
rearward. The eighth invention is applied to a rocking chair.
However, obviously, the eighth invention may be applied also to the
third to the seventh invention. In rocking chairs, a configuration
is widely employed that the seat is linked to the backrest.
Obviously, the present invention may be applied also to such a
chair of synchronous type.
[0043] Warp deformation in the backrest appears remarkably in a
rocking state. Thus, the effect of the present invention is
utilized especially under the eighth invention.
[Ninth Invention]
[0044] Among these, in a backrest of the ninth invention: a body
support part on which a body pressure of a seat occupant acts is
constructed from a plurality of areas divided into right and left
with a certain amount of interval in between; each area is
constructed from a large number of stays horizontally elongated in
the right and left directions; the stays in adjacent areas are
arranged in a manner of being deviated in the up and down
directions; adjacent stays in adjacent areas are linked together by
a linkage piece in an inclined attitude in front view; and thereby
the inclined attitudes of linkage pieces adjacent in the up and
down directions are opposite to each other.
[0045] In the ninth invention, each stay is in an attitude
horizontally elongated in the right and left directions. Thus,
basically, the body support part deforms such as to extend in the
right and left directions alone. Thus, the configuration excels in
the stability of supporting the body. That is, the deformation in
the body support part has directivity and hence a situation is
avoided that the body support part excessively follows the movement
of the body so as to be deformed. Thus, the configuration excels in
the stability of supporting the body.
[0046] Further, the linkage pieces are in an inclined attitude.
Thus, when the attitudes of the linkage pieces vary so that the
angle formed by linkage pieces adjacent in the up and down
directions becomes small, the interval of stays adjacent in the
right and left directions becomes wide. This realizes substantially
the same state as a situation that the body support part has
performed extensional deformation in the right and left directions.
By virtue of this, a high cushioning property can be ensured.
Further, each stay is deformed such as to be bent, twisted, or
like. Thus, the configuration excels also in the fit property to
the body.
[Tenth Invention]
[0047] In a backrest of the tenth invention, a group of stays are
in a longitudinal orientation. That is, in the tenth invention: a
body support part on which the body pressure of a seat occupant
acts is constructed from a plurality of areas divided into up and
down with a certain amount of interval in between; each area is
constructed from a large number of stays elongated vertically; the
stays in adjacent areas are arranged in a manner of being deviated
in the right and left directions; adjacent stays in adjacent areas
are linked together by a linkage piece in an inclined attitude in
front view; and thereby the inclined attitudes of linkage pieces
adjacent in the right and left directions are opposite to each
other.
[0048] In the eleventh invention, the body support part easily
performs extensional deformation in the right and left directions.
However, basically, the same effect as that of the ninth invention
is obtained.
[Eleventh Invention]
[0049] The eleventh invention is a preferable example of expansion
of the first invention or the second invention. In this invention,
the width of the linkage piece is smaller than the width of the
stay in front view. According to this configuration, in a state
that the supporting area for the body is enlarged so that the
stability of supporting the body is improved, deformation in the
linkage pieces is made easy so that the cushion can be
improved.
[Twelfth Invention]
[0050] The twelfth invention is a detailed example of the ninth
invention. In this invention, bases of linkage pieces adjacent in
the up and down or the right and left directions are close to each
other so that the linkage pieces adjacent in the up and down or the
right and left directions are formed in a V-shape
configuration.
[0051] The bases of linkage pieces adjacent in the up and down or
the right and left directions may be separate from each other.
Nevertheless, in this case, the number of linkage pieces is reduced
so that a possibility arises that the strength is degraded. In
contrast, in the configuration of the fourth invention, the linkage
pieces are continuous to each other without a gap in between. Thus,
the number of linkage pieces can be increased and hence the
strength of the body support part also can be ensured.
[Thirteenth Invention]
[0052] The thirteenth invention is detailed and preferable
implementation of the ninth invention. In this invention, the
configuration includes: a center area located in a center in the
right and left directions; and right and left side areas arranged
on both right and left sides thereof, the center area being
constructed from a group of center stays and the side area being
constructed from side stays, wherein the group of linkage pieces
for connecting together the group of center stays and the group of
side stays is formed in a zigzag configuration.
[0053] The number of areas constructing the body support part can
arbitrarily be set forth. Nevertheless, when an excessively large
number of areas is employed, the number of linkage pieces also
increases and hence a concern of excessively high flexibility is
caused unless any means is taken. In contrast, like in the
thirteenth invention, in a configuration constructed from one
center area and two side areas, the stability of supporting the
body and the cushioning property can be harmonized with each other
in a satisfactory manner and hence this configuration is
preferable.
[Fourteenth Invention]
[0054] The fourteenth invention is detailed and preferable
implementation of the ninth invention. In this invention, in the
portion of the lumbar support part for supporting a vicinity of the
lumbar of a seat occupant, the density of stays is high. In this
invention, the lumbar of the seat occupant is appropriately
supported and hence this configuration is useful in improvement of
the stability of the body of the user. Here, also in the tenth
invention, it is preferable to employ means for improving the
rigidity of the portion of the lumbar support part. In both the
first invention and the second invention, as the means for improves
the rigidity of the lumbar support part, different means from the
fourteenth invention may be employed like the plate thickness of
the stay is increased.
[Fifteenth Invention]
[0055] The fifteenth invention also is detailed and preferable
implementation of the ninth invention. In this invention, each stay
has a plate-shape configuration in which a plate thickness in the
frontward and rearward directions is smaller than a vertical width,
then a rib elongated in the right and left directions is formed in
a rear face of each stay, and then the rib also is connected
integrally to the linkage piece.
[0056] In this fifteenth invention, in a state that each stay is
made as thin as possible, necessary bending strength can be
ensured. Thus, this configuration is preferable for saving the
material (the resin). Further, since the rib and the linkage piece
are connected to each other, smooth deformation can be realized
with avoiding a situation that bending is concentrated on the end
part portion of the stay. Another advantage is also obtained that
stress concentration is prevented and hence durability is improved.
Here, the configuration that a rib is provided in the rear face of
the stay may be applied also to the tenth invention.
Effect of the Invention
[0057] By virtue of the present invention, comfort in a state of
leaning on a chair is improved. Further, the strength of the chair
can be ensured, the time and effort in manufacturing can be saved,
and variation in the quality can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0058] FIGS. 1A and 1B are diagrams showing an overall external
appearance of a chair according to an embodiment. FIG. 1A is a
perspective view taken from the front and FIG. 1B is a perspective
view taken from the rear.
[0059] FIGS. 2A and 2B are diagrams showing an overall
configuration of a chair. FIG. 1A is a partly disassembled
perspective view and FIG. 1B is a side view.
[0060] FIGS. 3A and 3B are disassembled views of a main part. FIG.
3A is a diagram in a state that a backrest is shifted in an
ordinary attitude. FIG. 3B is a diagram in a state that the
backrest is horizontally rotated and disassembled.
[0061] FIGS. 4A to 4C are diagrams showing the relationship between
a support device and a back frame. FIG. 4A is a disassembled
perspective view of a first support device and a back frame, FIG.
4B is a disassembled perspective view of a first support device, a
second support device, and a backrest, and FIG. 4C is a
disassembled perspective view of a second support device and a
backrest.
[0062] FIGS. 5A and 5B are disassembled views showing the
relationship between a first support device and a backrest.
[0063] FIGS. 6A and 6B are disassembled views showing the
relationship between a second support device and a backrest.
[0064] FIGS. 7A to 7C are explanation diagrams of a lumbar support
member. FIGS. 7A and 7B are disassembled perspective views and FIG.
7C is a plan view of a backrest.
[0065] FIG. 8 is a front view of a backrest.
[0066] FIG. 9 is a perspective view of a backrest viewed from the
front.
[0067] FIG. 10 is a perspective view of a backrest viewed from the
rear.
[0068] FIG. 11 is a disassembled view used for describing the
function.
DETAILED DESCRIPTION OF EMBODIMENTS
[0069] Next, an embodiment of the present invention is described
below with reference to the drawings. The present embodiment is
applied to a swivel chair widely used in offices or the like. Here,
in the embodiment and the claims given below, terms "frontward and
rearward" and "right and left" are used for identifying the
directions. Then, these directions are defined with reference to a
person ordinarily sitting on the chair.
[0070] (1). Outlines of Chair
[0071] As shown in FIGS. 1A to 2B, a chair includes as main
elements a leg device 1, a seat 2, and a backrest 3. The backrest 3
is attached to a back frame 4 arranged behind it. The leg device 1
includes: a leg pillar 5 in a vertical attitude; and a center tube
6 for supporting this. Five branched arms extend in radial
directions from the center tube 6. Then, a caster is attached to
the tip of each branched arm.
[0072] The leg pillar 5 is constructed from a gas cylinder of
extendable type provided with an inner cylinder and an outer
cylinder. As shown in FIG. 2B, a base 7 is attach to the upper end
of the leg pillar 5 and then the back frame 4 is linked through a
joint member 8 to the base 7 in a manner permitting rearward
inclination. Here, the back frame 4 and the joint member 8 may be
integrated together. The inner cylinder and the outer cylinder
constituting the leg pillar 5 are freely rotatable relatively.
Thus, the base 7 (and the seat 2 and the backrest 3) is freely
rotatable horizontally.
[0073] Although illustration is omitted, a rocking spring for
elastically supporting the rearward inclination of the back frame 4
is built in the base 7. In the seat 2, an intermediate member (not
shown) provided in the base 7 is attached in a manner permitting
rearward inclination and rearward movement about the front part
serving as a center. The intermediate member and the joint member 8
are linked together in a manner permitting relative movement by a
shaft horizontally elongated in the right and left directions. By
virtue of this, the seat 2 performs rearward movement and rearward
inclination in linkage with the rearward inclination of the
backrest 3.
[0074] The backrest 3 includes a main member fabricated from a raw
material of resin such as polypropylene by injection molding. In a
case that the backrest 3 includes a cushion and a skin material,
the backrest 3 and the main member need be distinguished from each
other. However, in the present embodiment, the entirety of the
backrest 3 is constructed from the main member and hence
distinction of these does not provide a substantial advantage.
Thus, for simplicity of description, the term "main member" is not
used and the term "backrest 3" is used.
[0075] The backrest 3 is constructed from a framework 9
constituting the outer periphery and a body support part 10 located
in the inside. As shown in FIG. 8, the framework 9 is formed in a
shape substantially close to a quadrangle by: a pair of side
members 9a constituting both right and left sides; an upper member
9b horizontally elongated in the right and left directions and
constituting the upper end part; and a lower member 9c horizontally
elongated in the right and left directions and constituting the
lower end.
[0076] The lower end of the backrest 3 is located close to the seat
surface. Within the backrest 3, a lumbar support member 11 for
supporting the lumbar of a seat occupant is arranged in the front
face at a height position corresponding to the lumbar of the seat
occupant. The body height and the preference depend on the
individual seat occupant. Thus, the lumbar support member 11 is in
a height adjustable manner.
[0077] The backrest 3 of the present embodiment has such a
constricted shape that the attaching part of the lumbar support
member 11 is the narrowest. However, employable configurations need
not be limited to this. That is, as the configuration of the
backrest 3, an arbitrary shape may be employed like: a
configuration that the width in the right and left directions is
substantially fixed; the shape of an inverted trapezium in which
the upper end is wide and the lower end is narrow; and the shape of
an inverted trapezium in which the upper end is narrow and the
lower end is wide.
[0078] For example, as shown in FIGS. 3A and 3B, the back frame 4
includes right and left vertically elongated members 4a inclined
such that the interval between these becomes close as going upward.
In the right and left vertically elongated members 4a, the upper
ends are connected integrally through a linkage part 4b.
[0079] Thus, the right and left vertically elongated members 4a
constitute a configuration of inverted V-shape. The lower ends of
the right and left vertically elongated members 4a are connected
integrally through a lower stay part 4c. Further, a frontward arm
part 4d is provided integrally at the lower end of the right and
left vertically elongated members 4a. The frontward arm part 4d and
the lower stay part 4c are connected to the joint member 8 shown in
FIG. 2A and 2B. For example, as clearly seen from FIG. 4B, the
vertically elongated member 4a of the back frame 4 is formed in an
L-shaped cross section having a back face plate and a side face
plate. Thus, a light-weight structure is obtained that is strong in
the frontward and rearward directions and the right and left
directions as well as against twist.
[0080] In the back frame 4 of the present invention, a resin molded
article or an aluminum die-cast article is employed. Instead,
fabrication may be performed by employing a metal plate or a
metallic pipe as the material. A composite article constructed from
materials of different kinds may be employed. Further, an integral
construction is not unavoidable. That is, for example, the right
and left vertically elongated members 4a may be separately
fabricated and then linked together at the upper ends, that is, may
be constructed from a plurality of component parts. A
shell-structured article also may be employed as the back frame
4.
[0081] Then, for example, as shown in FIGS. 3A and 3B, within the
backrest 3, the right-left middle part of the upper member 9b is
attached through a first support device 12 to the linkage part 4b
of the upper end of the back frame 4. Then, in a part above the
attaching part of the lumbar support member 11, the right and left
side members 9a are attached through second support devices 13 to
the vertically elongated member 4a of the back frame 4. This point
is described below in detail.
[0082] (2). Attaching Structure of Backrest
[0083] As shown in FIGS. 4A and 4B, the first support device 12
includes two spring parts 12a arranged in a V-shape in front view.
An upper attaching part 12b horizontally elongated in the right and
left directions is connected integrally to the upper ends of the
spring parts 12a. Then, a lower attaching part 12c protruding
rearward is connected integrally to the lower ends of the right and
left spring plate parts 12a. The first support device 12 is
fabricated from a raw material of resin such as polypropylene by
injection molding. The spring plate parts 12a are in an attitude
elongated in the up and down directions, however, has a plate shape
which is wide in front view and narrow in side view. Thus, bending
deformation can easily be caused by a force from the front.
[0084] The lower attaching part 12c is formed in the shape of a
block (the shape of a boss) horizontally elongated in the right and
left directions. A rear-side first recess 15 serving as a frontward
aperture into which the lower attaching part 12c is fitted is
formed in the linkage part 4b of the back frame 4. The lower
attaching part 12c is fixed with a first bolt 16 inserted into a
rear-side first recess 15 from below. As shown in FIG. 4A, in the
attaching part 12c of the first support device 12, a nut insertion
hole 17 into which a nut for the first bolt 16 is set is opened
rearward.
[0085] As shown in FIGS. 5A and 5B, the upper member 9b of the
backrest 3 has a triple structure in the inside and outside having
an outer wall, an inner wall 18, and an intermediate wall 19. Thus,
two elongated grooves 20 opened rearward are formed. Then, the
right-left middle part of the inner wall 19 is, for example, cut
off so that a front-side first recess 21 into which the upper
attaching part 12b of the first support device 12 is fitted is
formed. The upper attaching part 12b of the first support device 12
is fixed to the upper member 9b with a second bolt 22 inserted from
below.
[0086] A nut holding part 23 opened rearward is formed in the upper
member 9b of the backrest 3. On the other hand, in the upper
attaching part 12b of the first support device 12, a stopper piece
24 for abutting against the nut holding part 23 of the upper member
9b from the rear is provided such as to protrude upward.
[0087] The second support device 13 is fabricated from a raw
material of resin such as nylon resin having a high rigidity. Then,
as shown in FIGS. 5B and 5C, the second support device 13 includes
an arm part 13a having a band plate shape gradually bent into a
wave shape in plan view. At the rear end of the arm part 13a, a
rear boss part 13b is provided integrally. Then, at the front end
of the arm part 13a, a front boss part 13c is provided integrally.
The arm part 13a has such a rigidity that deformation is not easily
caused by the body pressure of the sitting person (however, slight
deformation may occur).
[0088] The rear boss part 13b is fitted into the rear-side second
recess 25 provided in the vertically elongated member 4a of the
back frame 4. A third bolt 26 is inserted into the rear-side second
recess 25 from below. A nut (not shown) into which the third bolt
26 is inserted is incorporated in the rear boss part 13b of the
second support device 13. A flange 13d overlapping with the opening
edge of the rear-side second recess 25 is provided in the rear boss
part 13b.
[0089] As clearly shown in FIGS. 6A and 6B, a front-side second
recess 27 into which a front boss 13c of the second support device
13 is fitted is formed in the side member 9a of the backrest 3. The
front-side second recess 27 has a substantially box-shaped external
appearance and then a bolt hole 28 through which a bolt (not shown)
is inserted is opened in the inner wall 27a. On the other hand, a
nut attaching groove 29 is provided in the front boss part 13c of
the second support device 13. Then, a bolt is inserted into the nut
arranged in the nut attaching groove 29.
[0090] In this case, a step part 30 for increasing the thickness of
the portion of the bolt hole 28 so as to enhancing the strength is
formed in an inner plate 25a of the front-side second recess 27. On
the other hand, a cut-off part 31 overlapping with the step part 30
of the front-side second recess 27 is formed in the front boss part
13c of the second support device 13. Further, a flange 13e
overlapping with the opening edge of the front-side second recess
27 is provided in the front boss part 13c of the second support
device 13.
[0091] (3). Lumbar Support Member
[0092] Next, the lumbar support member 11 is described below mainly
with reference to FIGS. 7A to 7C. The lumbar support member 11 is
composed of a molded article fabricated from a raw material of
resin and formed from a raw material such as polypropylene having
certain elasticity. Then, the lumbar support member 11 has a shape
horizontally elongated in the right and left directions and
crossing the backrest 3. In plan view, the lumbar support member 11
is gradually curved concave frontward. Further, in vertical
sectional side view, the lumbar support member 11 is slightly
curved convex frontward.
[0093] Slide boss members 34 having a prism shape and protruding
rearward are formed integrally at both right and left ends of the
lumbar support member 11. The slide boss member 34 is fitted, in a
freely slidable manner, into a guide frame part 35 elongated in the
up and down directions provided in the side member 9a of the
backrest 3. As shown in FIGS. 6A and 6B, the inner periphery of the
guide frame part 35 is constructed from a plate part and then the
front-side second recess 27 described above is connected integrally
to the upper end of the guide frame part 35.
[0094] As shown in FIGS. 7A to 7C, a frontward protruding part 36a
having a block shape and provided in a knob 36 is fitted into the
rear end of the slide boss member 34. The frontward protruding part
36a of the knob 36 is fixed to the slide boss member 34 with a bolt
(not shown). A nut insertion groove 37 is provided in the slide
boss member 34. The lumbar support member 11 can be held in a
manner that the height is adjusted stepwise. Then, as shown in FIG.
6A, as height adjusting means, a large number of stopper holes 38
are provided at a large number of vertical stages in the inner
plate of the guide frame part 35.
[0095] Then, a configuration is widely employed that a lumbar
support member is provided in the backrest. However, in general, in
many cases, the lumbar support member is arranged on the back side
of a cushion or on the back side of a mesh material. Nevertheless,
in a case that the cushion or the mesh material intervenes between
the lumbar support member and the body, in some cases, a person who
desires a strong "feeling of abutting" feels unsatisfaction.
Further, in some cases like a case that the backrests is not
provided with a cushion or a mesh, a lumbar support member need be
arranged on the near side of the back plate.
[0096] As an example of this, JP-A-2008-237333 discloses an
approach that in a configuration that a backrest is constructed
from a frame part and a back plate located in the inner side
thereof and then a large number of slits are provided in the back
plate, a lumbar support member is arranged on the near side of the
back plate. Further, this document discloses a configuration that
handles of clip type fitted onto a frame part from the outer side
are provided integrally in both right and left end parts of the
lumbar support member and then the frame part is elastically held
by the handles from below.
[0097] Nevertheless, in the configuration that the handles are
fitted onto the frame part from outside like in the above-mentioned
prior-art patent document, the handles run off to the right and
left outer sides of the frame part and hence a trouble is expected
that a person's clothes are caught in the handle or, alternatively,
an object abuts against the handle so that the handle is damaged.
Further, the handles maintain the height merely by friction and
hence a possibility arises that the lumbar support member is slid
such as to be raised or lowered by the body pressure of the seat
occupant.
[0098] In contrast, in the present embodiment, the slide bosses 34
provided in both right and left end parts of the lumbar support
member 11 penetrate the guide frame parts 35 of the framework 9.
Thus, the knobs 36 can be arranged such as not to run off the right
and left outer sides of the framework 9. By virtue of this, a
situation that the clothes are caught in the knob 36 or,
alternatively, an object abuts against it can be avoided or,
alternatively, suppressed remarkably. Further, it is also easy to
provide height holding means constructed from the stopper holes 38
for height adjustment of the guide frame part 35. Thus, the lumbar
support member 11 can be held at a desired height in a manner not
permitting deviation movement.
[0099] Here, the height adjusting means may employ various
configurations. In a case that the stopper holes 38 are provided in
the guide frame part 35 like in the embodiment, it is sufficient
that an elastic member fitted into and detached from the guide
frame part 35 is provided in the block-shaped frontward protruding
part of the knob 36. The guide frame part 35 has a certain amount
of frontward and rearward width and hence strength degradation is
not caused by the penetration of the slide boss member 34. The knob
36 may be fabricated in a simple plate shape and then may be
screwed to the slide boss member 34.
[0100] (4). Structure of Backrest
[0101] Next, within the backrest 3, details of the structure of the
body support part 10 are described below mainly with reference to
FIGS. 8 to 10. As shown in FIG. 8, in the present embodiment, the
body support part 10 includes: groups of horizontally elongated
side stays 40 connected to the right and left side members 9a; and
a group of horizontally elongated center stays 41 located between
the groups of side stays 40. Both groups of stays 40 and 41 are
arranged in a state of being deviated up and down. The center area
is constructed from the group of center stays 41 and the side areas
are constructed from the groups of side stays 40.
[0102] Then, both right and left ends of the center stays 41 and
the tips of the side stays 40 adjacent in the right and left
directions are connected integrally with linkage pieces (joint
stays) 42. In this case, there are slight gaps in the right and
left directions between the tips of the side stays 40 and the ends
of the center stays 41. Thus, the linkage pieces (the joint stays)
42 are in an inclined attitude in front view. Further, the center
stays 41 and the side stays 40 are arranged in a manner of being
deviated up and down and hence linkage pieces (joint stays) 42
adjacent in the up and down directions are in attitudes of opposite
orientation. Further, the bases of linkage pieces (the joint stays)
42 and stays 40 and 41 adjacent in the up and down directions are
connected integrally. Thus, the groups of linkage pieces (joint
stays) 42 have a zigzag shape in front view.
[0103] The backrest 3 is constricted such that the portion close to
the lower side becomes narrow in front view. Thus, together with
the side members 9a of the backrest 3, a shape curved concave
outward is formed. Further, the linkage pieces (the joint stays) 42
also are curved concave outward in front view such as to follow the
shape of the side members 9a. Further, the side member 9a and the
center stay 41 have substantially the same length in the right and
left directions.
[0104] The side stay 40 and the center stay 41 have a plate-shaped
structure whose front and rear faces are wide. However, as shown in
FIG. 10, a rib 43 is provided integrally in the rear faces of the
side stay 40 and the center stay 41. Thus, the cross sections of
the side stay 40 and the center stay 41 have a sideways T-shape.
The rear face of the rib 43 is in plane with the rear face of the
linkage piece (the joint stay) 42. The linkage piece (the joint
stay) 42 has an external appearance of a thin band plate and hence
can easily be deformed such that the angle of the sideways V
becomes wide or narrow. That is, in the lumbar support member 111,
the density of stays 140 and 141 is high. By virtue of this, the
lumbar support part has a higher rigidity than the other parts.
[0105] The groups of side stays 40 and center stays 41 are arranged
at a large number of vertical stages. Thus, a space 44 horizontally
elongated in the right and left directions is opened individually
between side stays 40 and between center stays 41 adjacent in the
up and down directions. Then, in the present embodiment, except for
the lumbar support part, the vertical width dimension of the space
44 is twice or the like of the vertical width of the stay 40 or 41.
In the lumbar support part, the vertical width dimension of the
space 44 is set substantially at the same level as the vertical
width of the stay 40 or 41. Thus, the lumbar support part has a
higher rigidity.
[0106] From the first, the vertical width and the pitch (the
density) of the side stay 40 and the center stay 41 may be set up
arbitrarily. For example, the vertical width dimension of the stay
40 or 41 and the space 44 may be set substantially at the same
level over the entirety in the up and down directions.
Alternatively, the vertical width dimension of the stay 40 or 41
may be set smaller than the vertical width dimension of the space
44 over the entirety.
[0107] Further, in the present embodiment, the body support part 10
has been constructed from two rows of the side stays 40 and one row
of the center stays 41. However, employable configurations need not
be limited to this. That is, the center stays 41 may be not
provided and then the body support part 10 may be constructed from
right and left side stays 40 and from one linkage piece (one joint
stay) 42 for connecting these. Alternatively, the body support part
10 may be constructed from two rows of the side stays 40 and two
rows of intermediate stays located between them. In a case that two
rows of the intermediate stays are provided, three linkage pieces
(three joint stays) 42 are necessary. Further, the body support
part 10 may be constructed from five rows of stay groups consisting
of two rows of the side stays 40, one row of the center stays 41,
and two rows of the intermediate stays. Further, the backrest 3 may
employ other configurations.
[0108] (5). Summary
[0109] Next, the operation is described below with reference to
FIG. 11. First, a rocking state is described below.
[0110] For example, the body pressure of a seat occupant in a
rocking state acts on the backrest 3 from the front as indicated by
an arrow F. Then, the load acting on the backrest 3 is supported by
the first support device 12 and the second support device 13. Then,
as indicated by an arrow Y, the first support device 12 can perform
bending deformation such that the upper end is moved rearward by
the load from the front in side view. On the other hand, as
indicated by an arrow X, the second support device 13 can perform
bending deformation such that the tip is moved rearward in plan
view. However, since the second support device 13 has a high
rigidity, the back frame 4 of the backrest 3 is firmly held by the
second support device 13 and hence the lumbar of the seat occupant
is held with satisfactory stability.
[0111] On the other hand, the moment by rocking acts largely on the
upper end part in the backrest 3. However, the first support device
12 has a lower rigidity than the second support device 13 and hence
easily performs warp deformation in accordance with the body
pressure. Thus, at the time of rocking, the backrest 3 can perform
warp deformation such that the upper end part thereof approaches
the upper end part of the back frame 4. This warp deformation of
the backrest 3 can improve the cushioning property at the time of
rocking.
[0112] Further, in a rocking state, when the person twists the
upper half body in the right or left direction or, alternatively,
shifts the shoulder in the right or left direction, the two right
and left spring parts 12a constituting the first support device 12
perform bending deformation unevenly so that the backrest 3 can be
deformed and twisted such as to follow the twist or the shift of
the body. Thus, the backrest 3 can follow the change of the
attitude of the body. As a result, comfort can be improved.
[0113] As clearly seen from FIG. 11, the backrest 3 is gradually
curved concave frontward in plan view. The degree of the curve is
largest in the vicinity of the lumbar support member 11 and then
the upper end part is in an almost flat state. Thus, in a state
that the lumbar is held such as not to be deviated right or left,
the shoulder (or the portion close to the shoulder) can easily be
shifted right and left. Also from this point, high comfort can be
obtained.
[0114] As shown in FIG. 2B, in a neutral state that the seat
occupant does not lean on the backrest 3, the backrest 3 is
slightly in a rearward inclined attitude and the lumbar support
member 11 is located on the most front side. Then, when the user
performs desk work such as PC operation, the user takes an attitude
that the lumbar abuts against the lumbar support member 11 of the
backrest 3. However, since the second support device 13 has a high
rigidity, the backrest 3 does not perform warp deformation in
association with the body pressure of the seat occupant in a
neutral state and hence the lumbar of the person is supported by
the backrest 3 with satisfactory stability. Thus, the upper half
body of the user does not become unsteady and is held in a
preferable attitude that the back is straightened. Thus, the
present configuration excels also in the attitude maintaining
function in a neutral state (a non-rocking state).
[0115] Since the side stays 40 and the center stays 41 are deviated
up and down and the linkage pieces (the joint stays) 42 are in a
zigzag configuration, the backrest 3 of the present embodiment can
perform warp deformation such that the body support part 10 swells
rearward in accordance with the body pressure of the seat occupant.
Thus, the present configuration excels in the fit property to the
body of the user and excels also in the follow-up property for the
movement of the body.
[0116] Further, when the linkage pieces (the joint stays) 42
adjacent in the up and down directions are deformed such that the
mutual opening angle (the angle of V) becomes small, a tendency
arises that the center stays 41 are deviated rearward. As a result,
the body support part 10 is deformed such as to swell rearward.
This improves the cushioning and the fit property to the body of
the user.
[0117] The present application is based on U.S. Provisional
Application for Patent (61/831,763) filed on Jun. 6, 2013, the
contents of which are incorporated herein by reference.
INDUSTRIAL APPLICABILITY
[0118] The present invention can provide a chair in which comfort
in a leaning-on state is improved. Further, a chair can be provided
in which the strength can be ensured, the time and effort in
manufacturing can be saved, and variation in the quality can be
prevented.
REFERENCE SIGN LIST
[0119] 1 Leg device [0120] 2 Seat [0121] 3 Backrest [0122] 4 Back
frame [0123] 5 Leg pillar [0124] 6 Center tube [0125] 7 Base [0126]
8 Joint member [0127] 9 Framework [0128] 9a Side member [0129] 9b
Upper member [0130] 9c Lower member [0131] 10 Body support part
[0132] 11 Lumbar support member [0133] 12 First support device
[0134] 12a Spring part [0135] 12b Upper attaching part [0136] 12c
Lower attaching part [0137] 13 Second support device [0138] 13a Arm
part [0139] 13b Rear boss part [0140] 13c Front boss part [0141]
13e Flange [0142] 15 Rear-side first recess [0143] 16 First bolt
[0144] 18 Inner wall [0145] 19 Intermediate wall [0146] 22 Second
bolt [0147] 23 Nut holding part [0148] 24 Stopper piece [0149] 25
Rear-side second recess [0150] 25a Inner plate [0151] 26 Third bolt
[0152] 27 Front-side second recess [0153] 28 Bolt hole [0154] 29
Nut attaching groove [0155] 30 Step part [0156] 31 Cut-off part
[0157] 34 Slide boss member [0158] 35 Guide frame part [0159] 36
Knob [0160] 36a Frontward protruding part [0161] 37 Nut insertion
groove [0162] 38 Stopper hole [0163] 40 Side stay [0164] 41 Center
stay [0165] 42 Linkage piece [0166] 43 Rib [0167] 44 Space
* * * * *