U.S. patent application number 12/305861 was filed with the patent office on 2010-09-23 for chair with automatically movable back support.
Invention is credited to Jong Ho Lee.
Application Number | 20100237674 12/305861 |
Document ID | / |
Family ID | 38015140 |
Filed Date | 2010-09-23 |
United States Patent
Application |
20100237674 |
Kind Code |
A1 |
Lee; Jong Ho |
September 23, 2010 |
CHAIR WITH AUTOMATICALLY MOVABLE BACK SUPPORT
Abstract
A chair with an automatically movable back, having a support,
and a seat and a back installed on the support. The chair comprises
a base frame coupled to a lower surface of the seat in such a way
as to define a space between the base frame and the seat; a
horizontal movement frame coupled to an upper surface of the base
frame to be moved forwards and rearwards, connected at left and
right ends thereof to a back frame which in turn is connected with
the back of the chair, and having on a lower surface thereof a
follower which receives force required for forward and rearward
movement; a vertical movement frame which has an upper surface
which is connected to the lower surface of the base frame and a
lower surface which is connected to the support, and which is
coupled to the support such that the vertical movement frame can
slide upwards and downwards with respect to the support; and
rotation force generation means installed in the vertical movement
frame to transmit rotation force generated by upward and downward
movement of the vertical movement frame to the follower such that
the horizontal movement frame can be moved forwards and
rearwards.
Inventors: |
Lee; Jong Ho; (Changwonsi
Gyongnam, KR) |
Correspondence
Address: |
IPLA P.A.
3550 WILSHIRE BLVD., 17TH FLOOR
LOS ANGELES
CA
90010
US
|
Family ID: |
38015140 |
Appl. No.: |
12/305861 |
Filed: |
June 20, 2007 |
PCT Filed: |
June 20, 2007 |
PCT NO: |
PCT/KR07/03000 |
371 Date: |
December 19, 2008 |
Current U.S.
Class: |
297/383 |
Current CPC
Class: |
A47C 7/54 20130101; A47C
7/40 20130101 |
Class at
Publication: |
297/383 |
International
Class: |
A47C 7/46 20060101
A47C007/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2006 |
KR |
10-2006-0056209 |
Claims
1. A chair with an automatically movable back, having a support,
and a seat and a back installed on the support, the chair
comprising: a base frame coupled to a lower surface of the seat in
such a way as to define a space between the base frame and the
seat; a horizontal movement frame coupled to an upper surface of
the base frame to be moved forwards and rearwards, connected at
left and right ends thereof to a back frame which in turn is
connected with the back of the chair, and having on a lower surface
thereof a follower which receives force required for forward and
rearward movement; a vertical movement frame having an upper
surface which is connected to a lower surface of the base frame and
a lower surface which is connected to the support, and coupled to
the support such that the vertical movement frame can slide upwards
and downwards with respect to the support; and rotation force
generation means installed in the vertical movement frame to
transmit rotation force, generated by upward and downward movement
of the vertical movement frame, to the follower such that the
horizontal movement frame can be moved forwards and rearwards.
2. The chair according to claim 1, wherein the support has a gas
cylinder and a piston, and the vertical movement frame is slidably
coupled to the piston.
3. The chair according to claim 2, wherein the vertical movement
frame comprises an upper frame and a lower frame which are
connected with each other, and at least one elastic member is
disposed between the upper frame and the lower frame.
4. The chair according to claim 3, wherein the rotation force
generation means comprises: a fixed shaft having a lower end which
is coupled to the piston and an upper end which passes through the
upper frame and is formed with a meshing portion; a meshing body
arranged in the upper frame to be meshed with the meshing portion
such that the meshing body can be rotated by upward and downward
movement of the vertical movement frame; and an intermediate
element connected to the meshing body and the follower to transmit
rotation force of the meshing body to the follower.
5. The chair according to claim 4, wherein a guide cylinder is
fitted around an outer surface of the lower end of the fixed shaft,
the lower frame is fitted around an outer surface of the guide
cylinder, and a plurality of balls is accommodated in at least one
groove defined in an outer surface of the guide cylinder such that
the lower frame can smoothly slide with respect to the guide
cylinder.
6. The chair according to claim 4, wherein the meshing portion and
the meshing body are meshed and operated in a gear type
fashion.
7. The chair according to claim 6, wherein the meshing portion
comprises a vertical rack gear, and the meshing body comprises a
pinion gear.
8. The chair according to claim 4, wherein the intermediate element
is directly or indirectly connected with the meshing body to be
rotated around a predetermined point, and is meshed with the
follower to transmit rotation force thereto.
9. The chair according to claim 8, wherein the intermediate element
is coupled to a rotation support member which is connected to a
shaft of the meshing body, has an arc-shaped configuration having
gear teeth formed on an outer surface thereof, and is meshed with
the follower.
10. The chair according to claim 4, wherein the follower comprises
a straight horizontal rack gear.
11. The chair according to claim 1, further comprising: braking
means for fixing the horizontal movement frame moved with the back
to an optional position.
12. The chair according to claim 11, wherein the braking means
comprises: a plurality of rods fastened on both ends thereof to be
spaced apart from the upper surface of the base frame, extending in
forward and rearward directions, and defined on lower surfaces
thereof with engagement grooves; and a tilting frame rotatably
connected to rear left and right portions of the horizontal
movement frame by a pin shaft, having the shape of a plate, and
formed on a front end thereof with engagement pieces to be engaged
into the engagement grooves of the rods, so that, when the tilting
frame is rotated upwards, the engagement pieces are engaged into
the engagement grooves of the rods to secure a position of the
horizontal movement frame.
13. The chair according to claim 12, wherein the tilting frame has
front brackets on front left and right portions thereof adjacent to
the engagement pieces, which are defined with slots, an adjustment
lever is rotatably coupled through the horizontal movement frame in
such a way as to pass through the slots of the front brackets, and
a cam is eccentrically fastened to the adjustment lever, such that,
as the adjustment lever is rotated, the cam pushes the tilting
frame upwards to secure the horizontal movement frame to an
optional position.
14. A chair with an automatically movable back, having a support,
and a seat and a back installed on the support, the chair
comprising: a base frame coupled to a lower surface of the seat in
such a way as to define a space between the base frame and the
seat, and having hollow pillars which project from a lower surface
of the base frame; a horizontal movement frame coupled to an upper
surface of the base frame to be moved forwards and rearwards,
connected at left and right ends thereof to a back frame which in
turn is connected with the back of the chair, and having on a lower
surface thereof a follower which receives force required for
forward and rearward movement; a connection housing coupled to the
support, open at an upper end thereof to define a space therein,
and having slide pillars into which the hollow pillars of the base
frame are respectively inserted; elastic members disposed between
the hollow pillars and the slide pillars to allow the base frame to
be moved upwards and downwards with respect to the connection
housing; and rotation force generation means formed in the
connection housing to transmit rotation force generated by upward
and downward movement of the base frame to the follower such that
the horizontal movement frame can be moved forwards and
rearwards.
15. The chair according to claim 14, wherein the rotation force
generation means comprises: a meshing portion fixedly installed in
the connection housing and formed on an outer surface thereof with
a vertically extending rack gear; a meshing body installed on
support brackets which are connected to the base frame between the
hollow pillars and project vertically downwards, and meshed with
the meshing portion to be rotated; and an intermediate element
connected with the meshing body and the follower and rotated to
linearly move the horizontal movement frame.
16. The chair according to claim 14, wherein one side end of the
base frame is bent to face downwards, engagement grooves are
defined in an edge of the bent side end of the base frame to create
prominences and depressions, a tilting frame is placed on the
horizontal movement frame in such a way as to cover the horizontal
movement frame and is projectedly formed with an engagement piece
on one side end thereof corresponding to the engagement grooves,
and an adjustment lever is rotatably installed through side walls
of the horizontal movement frame and the tilting frame and has an
eccentric cam fixed thereto, such that, as the adjustment lever is
rotated, the cam pushes the tilting frame upwards to engage the
engagement piece into one of the engagement grooves to thereby
limit movement of the horizontal movement frame.
17. The chair according to claim 14, wherein the connection housing
is connected with the support through a connection bracket which is
coupled to the support such that the connection housing is
rotatably connected to the connection bracket, and an angle
adjustment elastic member, which is coupled to the connection
bracket, and the connection housing are linked with each other so
that the connection housing can be inclined rearwards within a
predetermined range.
18. The chair according to claim 1, wherein the back of the chair
is rotatably coupled to left and right portions of the back frame
by way of connection shafts, an angle adjustment lever, which is
defined with a plurality of fixing grooves, is axially movably
coupled to an end of the connection shaft, which projects out of
one side of the back frame, such that fixing pins, which are formed
on the back frame, can be selectively locked into the respective
fixing grooves to adjust an inclination angle of the back, and an
elastic member is connected to a rear lower end of the back such
that the elastic member is coupled to a rear portion of the back
frame.
19. The chair according to claim 18, wherein one end of the elastic
member is coupled to a guide ring which is moved along a guide rod
fixedly installed on the back of the chair, and another end is
connected to an adjustment rod which is threadedly coupled to a
control rod so that the adjustment rod can be changed in its
position, the control rod being detachably attached in an opening
groove defined in the rear portion of the back frame.
20. The chair according to claim 19, wherein the opening groove is
open toward an upper surface of the back frame, such that, by
pushing the control rod fitted into the opening groove and removing
the control rod from the opening groove, the back can be rotated
forwards around the connection shafts in such a way as to be
folded.
Description
TECHNICAL FIELD
[0001] The present invention relates to a chair having a seat and a
back, and more particularly, to a chair having an automatically
movable back wherein the back of the chair can be automatically
moved by a user's weight to properly support the back of the user
even when the user sits on a seat without bringing his or her back
into contact with the back of the chair, thereby allowing the user
to have a correct sitting posture.
BACKGROUND ART
[0002] In general, a chair has a back for supporting the back of a
user who sits on the chair to help the user to rest in a
comfortable posture and protect the spine of the user.
[0003] It is generally not considered correct posture to sit by
placing the hips on the front portion of the seat. Therefore, only
when the hips are placed on the very rear portion of the seat and
the back of the user is brought into close contact with and
supported by the back of the chair can the spine of the user be
protected from bending.
[0004] Hence, the backs of chairs have been designed in
consideration of ergonomic aspects to protect the spines of
users.
[0005] To this end, conventional chairs are configured in a manner
such that the back of a chair can be elastically inclined
rearwards, or such that the back of a chair is divided into two
parts to support the back of a user on both sides of the spine to
thereby define a dual back structure which improves support quality
and comfort.
[0006] However, in the conventional chairs, since the back of the
chair is always fixedly positioned irrespective of the position on
the chair on which the user sits, if the user does not sit with
correct posture, in which his or her hips are placed on the very
rear portion of the seat, but sits on the front or middle portion
of the seat, the back of the user is spaced apart from the back of
the chair. As a consequence, because the back of the chair cannot
support the back of the user, the user experiences increased
fatigue, and if the incorrect posture becomes a habit, the spine
can be seriously influenced, as a result of which intervertebral
disc hernia may occur.
DISCLOSURE OF INVENTION
Technical Problem
[0007] Accordingly, the present invention has been made in an
effort to solve the problems occurring in the related art, and an
object of the present invention is to provide a chair with an
automatically movable back wherein the back of the chair can always
support the back of a user irrespective of the position where the
user sits on a seat, thereby decreasing the fatigue of the user,
enabling the user to assume a correct sitting posture, and
preventing spinal and musculoskeletal disorders.
Technical Solution
[0008] In order to achieve the above object, according to one
aspect of the present invention, there is provided a chair with an
automatically movable back, having a support, and a seat and a back
installed on the support, the chair comprising a base frame coupled
to the lower surface of the seat in such a way as to define a space
between the base frame and the seat; a horizontal movement frame
coupled to an upper surface of the base frame to be moved forwards
and rearwards, connected at left and right ends thereof to a back
frame which in turn is connected with the back of the chair, and
having on a lower surface thereof a follower which receives force
required for forward and rearward movement; a vertical movement
frame having an upper surface which is connected to the lower
surface of the base frame and a lower surface which is connected to
the support, and coupled to the support such that the vertical
movement frame can slide upwards and downwards with respect to the
support; and rotation force generation means installed in the
vertical movement frame to transmit rotation force generated by
upward and downward movement of the vertical movement frame to the
follower such that the horizontal movement frame can be moved
forwards and rearwards.
[0009] According to another aspect of the present invention, the
support has a gas cylinder and a piston, and the vertical movement
frame is slidably coupled to the piston.
[0010] According to another aspect of the present invention, the
vertical movement frame comprises an upper frame and a lower frame
which are connected with each other, and at least one elastic
member is disposed between the upper frame and the lower frame.
[0011] According to another aspect of the present invention, the
rotation force generation means comprises a fixed shaft having a
lower end which is coupled to the piston and an upper end which
passes through the upper frame and is formed with a meshing
portion; a meshing body arranged in the upper frame to be meshed
with the meshing portion such that the meshing body can be rotated
by upward and downward movement of the vertical movement frame; and
an intermediate element connected to the meshing body and the
follower to transmit rotation force of the meshing body to the
follower.
[0012] According to another aspect of the present invention, a
guide cylinder is fitted around the outer surface of the lower end
of the fixed shaft, the lower frame is fitted around the outer
surface of the guide cylinder, and a plurality of balls is
accommodated in at least one groove defined in the outer surface of
the guide cylinder such that the lower frame can smoothly slide
with respect to the guide cylinder.
[0013] According to another aspect of the present invention, the
meshing portion and the meshing body are meshed and operated in a
gear fashion.
[0014] According to another aspect of the present invention, the
meshing portion comprises a vertical rack gear, and the meshing
body comprises a pinion gear.
[0015] According to another aspect of the present invention, the
intermediate element is directly or indirectly connected with the
meshing body to rotate around a predetermined point, and is meshed
with the follower to transmit rotation force thereto.
[0016] According to another aspect of the present invention, the
intermediate element is coupled to a rotation support member which
is connected to the shaft of the meshing body, has an arc-shaped
configuration which has gear teeth formed on the outer surface
thereof, and is meshed with the follower.
[0017] According to another aspect of the present invention, the
follower comprises a straight horizontal rack gear.
[0018] According to another aspect of the present invention, the
chair further comprises braking means for fixing the horizontal
movement frame, moved together with the back, to a desired
position.
[0019] According to another aspect of the present invention, the
braking means comprises a plurality of rods fastened on both ends
thereof to be spaced apart from the upper surface of the base
frame, extending in forward and rearward directions, and defined on
lower surfaces thereof with engagement grooves; and a tilting frame
rotatably connected to rear left and right portions of the
horizontal movement frame by a pin shaft, having the shape of a
plate, and formed on a front end thereof with engagement pieces
that engage into the engagement grooves of the rods, so that, when
the tilting frame is rotated upwards, the engagement pieces are
engaged into the engaging grooves of the rods to secure the
position of the horizontal movement frame.
[0020] According to another aspect of the present invention, the
tilting frame has front brackets on front left and right portions
thereof adjacent to the engagement pieces, which are defined with
slots, an adjustment lever is rotatably coupled through the
horizontal movement frame in such a way as to pass through the
slots of the front brackets, and a cam is eccentrically fastened to
the adjustment lever, such that, as the adjustment lever is
rotated, the cam pushes the tilting frame upwards to secure the
horizontal movement frame at a desired position.
[0021] According to another aspect of the present invention, there
is provided a chair with an automatically movable back, having a
support, and a seat and a back installed on the support, the chair
comprising a base frame coupled to the lower surface of the seat in
such a way as to define a space between the base frame and the
seat, and having hollow pillars which project from the lower
surface of the base frame; a horizontal movement frame coupled to
the upper surface of the base frame to be moved forwards and
rearwards, connected at left and right ends thereof to a back frame
which in turn is connected with the back of the chair, and having
on the lower surface thereof a follower which receives force
required for forward and rearward movement; a connection housing
coupled to the support, open at an upper end thereof to define a
space therein, and having slide pillars into which the hollow
pillars of the base frame are respectively inserted; elastic
members disposed between the hollow pillars and the slide pillars
to allow the base frame to move upwards and downwards with respect
to the connection housing; and rotation force generation means
formed in the connection housing to transmit rotation force
generated by upward and downward movement of the base frame to the
follower such that the horizontal movement frame can be moved
forwards and rearwards.
[0022] According to another aspect of the present invention, the
rotation force generation means comprises a meshing portion fixedly
installed in the connection housing and formed on the outer surface
thereof with a vertically extending rack gear; a meshing body
installed on support brackets which are connected to the base frame
between the hollow pillars, project vertically downwards, and are
meshed with the meshing portion so as to be rotated; and an
intermediate element connected with the meshing body and the
follower and rotated to linearly move the horizontal movement
frame.
[0023] According to another aspect of the present invention, one
side end of the base frame is bent to face downwards, engagement
grooves are defined on the edge of the bent side end of the base
frame to create prominences and depressions, a tilting frame is
placed on the horizontal movement frame in such a way as to cover
the horizontal movement frame and is projectedly formed with an
engagement piece on a side end thereof that corresponds to the
engagement grooves, and an adjustment lever is rotatably installed
through side walls of the horizontal movement frame and the tilting
frame and has fixed thereto an eccentric cam, such that, as the
adjustment lever is rotated, the cam pushes the tilting frame
upwards to engage the engagement piece into one of the engagement
grooves to thereby limit the movement of the horizontal movement
frame.
[0024] According to another aspect of the present invention, the
connection housing is connected with the support through a
connection bracket which is coupled to the support such that the
connection housing is rotatably connected to the connection
bracket, and an angle adjustment elastic member, which is coupled
to the connection bracket, and the connection housing are linked to
each other so that the connection housing can be inclined rearwards
within a predetermined range.
[0025] According to another aspect of the present invention, the
back of the chair is rotatably coupled to left and right portions
of the back frame by way of connection shafts, an angle adjustment
lever, which is defined with a plurality of fixing grooves, is
coupled to an end of the connection shaft so as to be axially
movable, the connection shaft projecting out of one side of the
back frame, such that fixing pins, which are formed on the back
frame, can be selectively locked into the respective fixing grooves
to adjust the inclination angle of the back, and an elastic member
is connected to a rear lower end of the back such that the elastic
member is coupled to the rear portion of the back frame.
[0026] According to still another aspect of the present invention,
the elastic member has one end coupled to a guide ring which is
moved along a guide rod fixedly installed on the back of the chair
and the other end connected to an adjustment rod which is
threadedly coupled to a control rod so that the position of the
adjustment rod can be changed, the control rod being detachably
attached in an opening groove defined in the rear portion of the
back frame.
[0027] According to a still further aspect of the present
invention, the opening groove is open toward the upper surface of
the back frame, such that, by pushing the control rod fitted into
the opening groove and removing the control rod from the opening
groove, the back can be rotated forwards around the connection
shafts in such a way as to be folded.
ADVANTAGEOUS EFFECTS
[0028] Thanks to the features of the chair having an automatically
movable back according to the present invention, advantages are
provided in that, regardless of where a user sits on a seat, the
back of the chair is automatically moved forwards to correctly
support the back of the human body so that a user can sit with his
or her back straightened naturally. Therefore, it is possible to
sit in a correct sitting posture and protect the spine, so that
spinal and musculoskeletal disorders are prevented.
[0029] Also, when compared to the conventional art, convenience is
improved and costs for storing and moving the chair can be
reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a schematic perspective view illustrating the
structure of a chair with an automatically movable back in
accordance with the present invention;
[0031] FIG. 2 is a schematic side sectional view illustrating a
first preferred embodiment of the present invention;
[0032] FIG. 3 is a side sectional view illustrating main parts;
[0033] FIG. 4 is a front sectional view illustrating the main
parts;
[0034] FIG. 5 is a plan view illustrating the main parts;
[0035] FIG. 6 is a front view illustrating a connection shaft;
[0036] FIG. 7 is a view illustrating the assembled state of an
angle adjustment lever;
[0037] FIG. 8 is a front view of the angle adjustment lever;
[0038] FIG. 9 is an exploded perspective view illustrating the main
parts of a chair in accordance with a fourth embodiment of the
present invention;
[0039] FIG. 10 is a sectional view illustrating the main parts in
an assembled state; and
[0040] FIG. 11 is a sectional view illustrating a fifth embodiment
of the present invention.
DESCRIPTION OF REFERENCE NUMERALS FOR MAIN PARTS IN DRAWINGS
[0041] 100: support 120: piston [0042] 200: seat 300: back [0043]
310: back frame 320: connection shaft [0044] 330: angle adjustment
lever [0045] 340: elastic members [0046] 400: base frame 500:
horizontal movement frame [0047] 510: follower 600: vertical
movement frame [0048] 610: upper frame 620: lower frame [0049] 700:
rotation force generation means [0050] 710: fixed shaft [0051] 720:
rolling element 730: intermediate element [0052] 740: guide
cylinder 800: braking means [0053] 810: rod 820: tilting frame
[0054] 830: adjustment lever 840: cam
BEST MODE FOR CARRYING OUT THE INVENTION
[0055] Hereafter, reference will now be made in greater detail to a
preferred embodiment of the invention, an example of which is
illustrated in the accompanying drawings. It is to be readily
understood that, since the drawings attached herein exemplarily
embody the technical idea of the present invention, the scope of
the present invention is not limited by the illustration of the
drawings.
[0056] FIG. 1 is a schematic perspective view illustrating the
structure of a chair with an automatically movable back in
accordance with the present invention, and FIG. 2 is a schematic
side sectional view illustrating a first preferred embodiment of
the present invention.
[0057] As can be seen from the drawings, the present embodiment
illustrates a state in which the present invention is applied to an
office chair which has wheels. However, it is to be readily
understood that the present invention is not limited to this
particular illustration, but can be applied to a vehicle seat, etc.
Basically, the chair has a support 100, and a seat 200 and a back
300 which are installed on the support 100. The support 100 can be
appropriately configured depending upon the kind of chair, the
installation place, etc.
[0058] One of the important features of the present invention
resides in that, when a user sits on the seat 200, the back 300 is
automatically moved to be brought into contact with the back of the
user so that the user can sit with a correct sitting posture. To
this end, the chair further has a base frame 400, a horizontal
movement frame 500, a vertical movement frame 600, and rotation
force generation means 700.
[0059] FIG. 3 is a side sectional view illustrating main parts,
FIG. 4 is a front sectional view illustrating the main parts, and
FIG. 5 is a plan view illustrating the main parts.
[0060] The base frame 400 is coupled to the lower surface of the
seat 200 and is fastened to the seat 200. Actually, a space is
defined between the base frame 400 and the seat 200, excluding the
portions where the base frame 400 is locked to the lower surface of
the seat 200 by means of bolts, etc.
[0061] The horizontal movement frame 500 is installed on the upper
surface of the base frame 400. The horizontal movement frame 500 is
coupled to the base frame 400 to be moved forwards and rearwards,
and a back frame 310 is connected to the left and right sides of
the horizontal movement frame 500. The back frame 310 is connected
with the horizontal movement frame 500 in such a way as not to
interfere with the seat 200, and extends above the seat 200. The
back 300 is connected to the back frame 310. A follower 510 is
coupled to the center portion on the lower surface of the
horizontal movement frame 500 to receive force required for forward
and rearward movement thereof.
[0062] In the present embodiment, as shown in the drawings, the
left and right sides of the base frame 400 are bent to have a
U-shaped section. In correspondence with this, a plurality of
rollers `r` is attached to the lower ends of the left and right
sides of the horizontal movement frame 500 such that the horizontal
movement frame 500 can be linearly moved along the base frame
400.
[0063] The vertical movement frame 600 is installed on the lower
surface of the base frame 400, and the lower end of the vertical
movement frame 600 is connected with the support 100. In
particular, the vertical movement frame 600 is coupled to the
support 100 such that the vertical movement frame 600 can slide
upwards and downwards relative to the support 100. When a load is
applied to the seat 200, the base frame 400, the horizontal
movement frame 500 and the vertical movement frame 600 are lowered.
Conversely, when the load applied to the seat 200 is removed, the
vertical movement frame 600 is raised to its original position. At
this time, the vertical movement frame 600 can be raised relative
to the support 100 due to disposal of elastic members 630 between
the support 100 and the vertical movement frame 600 so that, when
the applied load is removed, the vertical movement frame 600 can be
returned to its original position. This will be described later in
detail.
[0064] If the user sits on the seat 200, the back frame 310 and the
back 300, which are connected with the horizontal movement frame
500, are moved forwards to be brought into contact with the back of
the user. Driving force for forward and rearward movement of the
horizontal movement frame 500 is generated by the rotation force
generation means 700, which is installed in the vertical movement
frame 600. The rotation force generation means 700 generates
rotation force in conjunction with the upward and downward movement
of the vertical movement frame 600 and transmits the rotation force
to the follower 510, which is provided to the horizontal movement
frame 500 so that rotational movement is converted into linear
movement.
[0065] The main technical characteristic of the present invention
resides in that the automatic movement of the back 300 is realized
through a mechanical system, more specifically, in that the
rotation force generated through the upward and downward movement
of the vertical movement frame 600 is transmitted to the follower
510 of the horizontal movement frame 500, and thereby the
horizontal movement frame 500 is linearly moved forwards and
rearwards along the base frame 400. The rotation force generation
means 700, which will be described below in further detail, is only
an example of realization of the linear movement of the horizontal
movement frame 500, and therefore, it is to be noted that various
modifications of the rotation force generation means 700 fall under
the scope of the present invention as long as they can be easily
accomplished by a person having ordinary knowledge in the art and
they fall within the technical idea of the present invention.
[0066] In constructing the present invention, the support 100
serves as a part for supporting the load applied to the seat 200.
The support 100 can be fixedly installed at a specified location on
the ground, or can be coupled to a wheel frame which is provided
with wheels for allowing movement.
[0067] The support 100 is constructed in the same manner as that
provided in the conventional chair. Preferably, in order to permit
height adjustment of a chair, the support 100 comprises a gas
cylinder 110 and a piston 120. The vertical movement frame 600 is
connected to the piston 120, which projects from the gas cylinder
110. Since the height adjustment mechanism of the chair is well
known in the art, a detailed description thereof will be omitted
herein.
[0068] In the present embodiment, the vertical movement frame 600
is divided into two parts, that is, an upper frame 610 and a lower
frame 620. Elastic members 630 are disposed between the upper frame
610 and the lower frame 620 in a manner such that the lower ends of
the elastic members 630 abut a fixed shaft 710 constituting the
rotation force generation means 700, which will be described later.
Due to the presence of the elastic members 630, if the load applied
to the seat 200 is removed, the vertical movement frame 600 and the
parts other than the rotation force generation means 700, which are
lowered, are raised to their original positions. It is possible for
the vertical movement frame 600 to be integrally constructed. In
the present embodiment, the vertical movement frame 600 is divided
into two parts in consideration of convenience in fabrication and
assembly thereof.
[0069] The detailed structure of the rotation force generation
means 700, which is installed in the vertical movement frame 600,
will be explained below. The rotation force generation means 700
includes, as its main component elements, the fixed shaft 710, a
meshing body 720 and an intermediate element 730. The fixed shaft
710 has a lower end which is fixed to the piston 120 and an upper
end which extends through the upper frame 610. As shown in the
drawings, it is preferred that the fixed shaft 710 have a large
diameter portion 710a and a small diameter portion 710b having
different diameters. A groove is defined through the large diameter
portion 710a, which constitutes the lower portion of the fixed
shaft 710, and the piston 120 is fitted into the groove. The small
diameter portion 710b of the fixed shaft 710 projects through the
upper frame 610, and a meshing portion 711 is formed on the upper
end of the small diameter portion 710b. The meshing portion 711 is
meshed with the meshing body 720, which will be described later in
detail, to allow the meshing body 720 to rotate.
[0070] The vertical movement frame 600 is coupled to the support
100 in a manner such that it can be moved upwards and downwards. In
the present embodiment, to this end, a guide cylinder 740 is fitted
around the outer surface of the fixed shaft 710, and the vertical
movement frame 600 is fitted around the outer surface of the guide
cylinder 740. The way in which the vertical movement frame 600 is
slidably coupled to the support 100 can be changed in various ways.
It is to be noted that the illustration is only one example
thereof.
[0071] Meanwhile, in order to ensure smooth upward and downward
movement of the vertical movement frame 600 (more specifically, the
lower frame 620) which is fitted around the guide cylinder 740,
preferably, a plurality of grooves is defined in the outer surface
of the guide cylinder 740, and a plurality of balls `b` is
accommodated in the grooves so that sliding can be easily
accomplished.
[0072] The meshing body 720, which is directly meshed with the
meshing portion 711 formed on the fixed shaft 710, will be
described below. The meshing body 720 is rotatably arranged in the
upper frame 620 which constitutes the vertical movement frame 600.
That is to say, the meshing body 720 is fitted around the
horizontal shaft 781, which is installed to pass through the upper
frame 610 in leftward and rightward directions, such that the
meshing body 720 can be rotated around the horizontal shaft 781.
The meshing body 720 is meshed with the meshing portion 711 of the
fixed shaft 710, which is fixedly installed at a predetermined
position, such that the meshing body 720 can be rotated by the
meshing portion 711 when the vertical movement frame 600 implements
vertical movement.
[0073] Preferably, the meshing body 720 and the meshing portion
711, which is formed on the upper end of the fixed shaft 710, are
meshed with each other in a gear fashion. In particular, the
meshing body 720 may comprise a pinion gear, and the meshing
portion 711 may comprise a vertically extending rack gear.
Nevertheless, since it is sufficient to generate rotation force in
the meshing body 720 by way of friction between the meshing body
720 and the meshing portion 711, means other than the gear type may
be employed.
[0074] When rotation force is generated in the meshing body 720 due
to interaction between the meshing body 720 and the meshing portion
711, the rotation force is transmitted to the follower 510 via the
intermediate element 730 which is connected with the meshing body
720, as a result of which the horizontal movement frame 500 can be
linearly moved. The intermediate element 730 indicates an element
which is directly or indirectly connected with the meshing body 720
and rotates along the same locus. The intermediate element 730
transmits rotation force to the follower 510 through gear
meshing.
[0075] Preferably, the follower 510 comprises a horizontally
extending rack gear which has a linear configuration. The
intermediate element 730, which rotates along the same locus, has
an arc-shaped configuration and is formed on the outer surface
thereof with gear teeth which are meshed with the horizontal rack
gear constituting the follower 510.
[0076] The intermediate element 730 can be directly and integrally
connected to the meshing body 720, or can be coupled to a rotation
support member 722 which is connected with the horizontal shaft 781
on which the meshing body 720 is installed, to transmit rotation
force.
[0077] Hereinbelow, a second embodiment of the chair having an
automatically movable back according to the present invention will
be described below. The main technical feature of the second
embodiment resides in that braking means 800 is further provided to
allow the horizontal movement frame 500, which is linearly moved in
a horizontal direction along the base frame 400, to be fixed at an
optional position.
[0078] In the chair according to the present invention, when the
user sits on the seat 200, the back 300 of the chair is moved until
the back 300 is brought into contact with the back of the user. At
this time, since the back 300 is connected with the horizontal
movement frame 500 via the back frame 310, the back 300 pushes the
back of the user when the user sits on the seat 200. However, as
the case may be, it may be necessary to fix the position of the
back 300 so as to prevent the back 300 from pressing the back of
the user with excessive force.
[0079] The braking means 800 has, as its main component parts, rods
810 and a tilting frame 820. Each rod 810 is installed on the base
frame 400. A plurality of rods 810 is provided to extend in forward
and rearward directions such that they are spaced apart from the
upper surface of the base frame 400, excluding both ends thereof,
at which they are secured to the base frame 400. A plurality of
engagement grooves 811 is defined at regular intervals on the lower
surface of each rod 810. In the present embodiment, two rods 810
are provided so that balance can be maintained in the leftward and
rightward directions.
[0080] The tilting frame 820 is rotatably connected to the rear
left and right portions of the horizontal movement frame 500 by
means of a pin shaft 821. The tilting frame 820 has the shape of a
plate which covers the upper surface of the horizontal movement
frame 500, and is formed on the front end thereof with engagement
pieces 822 that engage into the engagement grooves 811 of the rods
810. The engagement pieces 822 are fitted around the rods 810.
Before the tilting frame 820 is pivoted upwards, the tilting frame
820 can be moved along with the horizontal movement frame 500 in
the forward and rearward directions. However, if the tilting frame
820 is pivoted upwards, as the engagement pieces 822 are engaged
into the engagement grooves 811, forward and rearward movement of
the horizontal movement frame 500 is prevented.
[0081] When the tilting frame 820 is provided, the back frame 310
is coupled to the upper surface of the tilting frame 820, and
accordingly, when the horizontal movement frame 500 is moved
forwards and rearwards, the back 300 can be simultaneously moved
therewith. If the user initially sits on the seat 200, the back 300
is moved to be brought into close contact with the back of the
user. Then, if the back 300 is slightly pushed rearwards by
inclining the user's body, the tilting frame 820, which is
connected with the back frame 310, is pivoted upwards, and the
engagement pieces 822 are engaged into the engagement grooves 811,
as a result of which further forward movement of the back 300 is
prevented. In this regard, in the case where the braking means 800
is simply composed of the tilting frame 820 and the rods 810, if
the user rises from the seat 200, the horizontal movement frame 500
always returns to its original position.
[0082] In the structure of the braking means 800, it is more
preferred that a user be able to fix the horizontal movement frame
500 at an optional position so that the back 300 does not move even
when the user rises from the seat 200. To this end, an adjustment
lever 830 having a cam 840 fastened thereto is provided such that a
user can selectively pivot the tilting frame 820 upwards to hold
the back 300 in a fixed state.
[0083] In greater detail, front brackets 823, which are defined
with track-shaped slots 824, are formed on the front left and right
portions of the tilting frame 820. The adjustment lever 830 is
rotatably coupled to the horizontal movement frame 500 in such a
way as to pass through the slots 824 of the front brackets 823.
Preferably, a handle is fastened to one end of the adjustment lever
830 to allow the user to manipulate the adjustment lever 830.
Perforations, which are defined through the left and right portions
of the horizontal movement frame 500 to allow the adjustment lever
830 to pass therethrough, have the sectional shape of a circle
having diameter corresponding to that of the adjustment lever 830,
so that the rotation of the adjustment lever 830 is not hindered.
The adjustment lever 830 has the shape of an elongate rod, and the
cam 840 is fastened to the adjustment lever 830 at an optional
position inside the horizontal movement frame 500. The cam 840 has
an eccentric configuration. In a portion which corresponds to the
position of the cam 840, the horizontal movement frame 500 is
partially open such that the cam 840 can project through the
horizontal movement frame 500 to be brought into contact with the
tilting frame 820.
[0084] As the adjustment lever 830, which passes through the
horizontal movement frame 500 and the tilting frame 820, is
rotated, the cam 840 upwardly pushes the tilting frame 820, which
is positioned above the horizontal movement frame 500. Due to the
fact that the adjustment lever 830 passes through the slots 824
which are defined through the front brackets 823 which are formed
on the front left and right portions of the tilting frame 820, as
force is upwardly applied to the cam 840, which is brought into
contact with the tilting frame 820, only the tilting frame 820 is
pivoted upwards along the slots 824. Pivotal movement of the
tilting frame 820 occurs around the pin shaft 821, and the movement
of the horizontal movement frame 500 is prevented due to engagement
of the engagement pieces 822 in the engagement grooves 811. If the
user wants to adjust the position of the back 300, the adjustment
lever 830 must be rotated to release contact between the cam 840
and the tilting frame 820 to thereby return the tilting frame 820
to a horizontal state.
[0085] Hereafter, a third embodiment of the chair with an
automatically movable back according to the present invention will
be described below with reference to FIGS. 2 through 8. FIG. 6 is a
front view illustrating a connection shaft, FIG. 7 is a view
illustrating the assembled state of an angle adjustment lever, and
FIG. 8 is a front view of the angle adjustment lever.
[0086] As can be seen from these drawings, the third embodiment of
the present invention is characterized in that, in addition to the
horizontal movement of the back 300 and the horizontal movement
frame 500, the back 300 can be rotated to enable adjustment of the
angle of the back 300.
[0087] In this embodiment, the back 300 of the chair is coupled to
the left and right portions of the back frame 310, which is
connected with the horizontal movement frame 500 or the tilting
frame 820, by means of connection shafts 320 to form a rotatable
structure. The connection shafts 320 provide the rotation center of
the back 300. In the chair according to the present invention, the
back frame 310, which is connected with the horizontal movement
frame 500, is formed to extend upwards from below the seat 200 to
be positioned higher than the seat 200 such that the back frame 310
can serve as an armrest. Due to this fact, the connection shafts
320 are connected to the back 300 at a position higher than the
lower end of the back 300. In the case of chairs in general, the
position where the back of the chair is rotated or inclined is
defined to correspond to the lower end of the back. In this case,
when the back is rotated or inclined, since a space is created
between the back of the chair and a user's back or hips, the spine
of the user is likely to be adversely influenced, thus leading to a
disorder.
[0088] Conversely, in the present invention, due to the fact that
the rotation point of the back 300 is positioned higher than the
lower end of the back 300, that is, it corresponds to a position
between the shoulder and the elbow of the user, even when the back
300 is inclined, since the portion of the back 300 positioned lower
than the rotation point of the back 300 can be moved forwards to be
brought into close contact with the back and the hips of the user,
the problem caused in general chairs can be solved.
[0089] The connection shafts 320 are fitted from the outside of the
back frame 310 into the back 300. An angle adjustment lever 330 is
coupled to the connection shaft 320, which projects from either the
left or the right side of the back frame 310. Alternatively, angle
adjustment levers 330 may be coupled to the respective connection
shafts 320, which project from both left and right sides of the
back frame 310. The angle adjustment lever 330 can be axially moved
relative to the connection shaft 320, and is defined with a
plurality of depressed or perforated fixing grooves 331 adjacent to
the edge thereof. In the present embodiment, two depressed fixing
grooves 331 are oppositely defined adjacent to the edge of the
angle adjustment lever 330.
[0090] Meanwhile, corresponding to the fixing grooves 331, fixing
pins 311 are projectedly formed on the back frame 310, such that
the fixing pins 311 can be selectively locked into the respective
fixing grooves 331. Due to the fact that the angle adjustment lever
330 can be axially moved relative to the connection shaft 320, if
the angle adjustment lever 330 is pulled outward, the fixing
grooves 331 are released from the fixing pins 311, so that the back
300 can be rotated. Conversely, if the angle adjustment lever 330
is pushed inward toward the back frame 310, the fixing grooves 331
are coupled to the fixing pins 311, so that the back 300 cannot be
rotated.
[0091] With the back 300 and the angle adjustment lever 330
connected to the connection shaft 320, if the back 300 is inclined,
the angle adjustment lever 330 is also rotated in the same
direction. The angle adjustment lever 330 can be axially moved with
respect to the connection shaft 320 within a predetermined distance
and can be integrally rotated with the connection shaft 320. In
order to realize the axial movement of the angle adjustment lever
330 with respect to the connection shaft 320, as shown in FIG. 6,
two guide grooves 321 are defined on the outer surface of the
connection shaft 320 adjacent to the outer end thereof, and in
correspondence with this, a plurality of balls 332 is accommodated
in the angle adjustment lever 330 and is supported by springs 333
such that the balls 332 are biased by the springs 333 into either
one of the guide grooves 321. Accordingly, as the angle adjustment
lever 330 is pushed or pulled by the user, it is axially moved with
respect to the connection shaft 320 between the guide grooves
321.
[0092] The angle of the fixing grooves 331 with respect to the
connection shaft 320 defines the maximum angle through which the
back 300 can be rotated in use of the chair. When the chair is not
used, by releasing the fixing grooves 331 from the fixing pins 311,
the back 300 can be completely folded.
[0093] Preferably, one end of an elastic member 340 is connected to
the rear lower end of the back 300, and the other end of the
elastic member 340 is connected to the rear portion of the back
frame 310. As the elastic member 340, various kinds of conventional
elastic members can be employed. In the present embodiment, a coil
spring is employed as the elastic member 340. Due to the fact that
the back 300 and the back frame 310 are connected with each other
by the elastic member 340, if the user pushes and inclines the back
300 rearwards, the elastic member 340 is tensed, and returning
force for returning the back 300 to the original position is
applied to the back 300.
[0094] When installing the elastic member 340, while it is possible
to simply connect both ends of the elastic member 340 directly to
the back 300 and the back frame 310, it is more preferable to use
the structure described below.
[0095] When the coil spring is employed as the elastic member 340,
in order to connect the elastic member 340 to the back 300 and the
back frame 310, a guide rod 341, a guide ring 342, a control rod
343 and a variable rod 344 are additionally provided. The guide rod
341 is installed on the center portion of the rear surface of the
lower end of the back 300, and the guide ring 342 is slidably
fitted around the guide rod 341. One end of the elastic member 340
is connected to the guide ring 342.
[0096] The control rod 343 and the variable rod 344 are used as
means for connecting the other end of the elastic member 340 to the
back frame 310. The control rod 343 is coupled to the rear end of
the back frame 310 at a position which is in the same vertical
plane as the guide rod 341. The variable rod 344 is threadedly
coupled to the control rod 343, and the other end of the elastic
member 340 is connected to the variable rod 344. The control rod
343 can be rotated in a state in which it is fitted into the
opening groove 312 defined in the back frame 310. Since the
position of the variable rod 344 can be changed by the rotation of
the control rod 343, it is possible to adjust the initial elastic
force of the elastic member 340.
[0097] Specifically, in the present invention, the elastic member
340 has a technical characteristic in that, as the back 300 is
inclined rearwards, the guide ring 342 connected to the elastic
member 340 is gradually moved upwards along the guide rod 341. In
comparison with the conventional case, in which the position of one
end of the elastic member, which is connected to the back 300, is
fixed, since the position of one end of the elastic member 340 can
be changed, assuming that the back 300 is inclined by the same
angle, the force that must be applied by the user to the back 300
is not greatly increased, and the angle of the back 300 can be
adjusted by the application of a small force.
[0098] When installing the control rod 343 in the opening groove
312 which is defined in the back frame 310, while it is possible to
couple the control rod 343 by simply defining a hole in the back
frame 310 as the opening groove 312, in the present embodiment, it
is intended that the control rod 343 be able to be released from
the back frame 310 as the occasion demands, so that the back 300
can be folded forward to be held in a substantially horizontal
state. In the conventional art, because the back of a chair extends
above the seat of the chair, when moving to a new residence or
delivering or storing the chair, due to the height which is
occupied by the back of the chair, inconvenience is caused and
space utilization efficiency is deteriorated. However, in the
present invention, since the back of the chair can be folded as the
occasion demands, the operations of storing or delivering the chair
can be conveniently implemented, and costs can be saved.
[0099] To this end, the opening groove 312 is defined to be open
toward the upper surface of the back frame 310. The sectional shape
of the opening groove 312 may be variously changed. However, in
order to prevent the control rod 343 from being unintentionally
released after fitting the control rod 343 into the opening groove
312, it is appropriate to provide a stopper (not shown) to the back
frame 310.
[0100] When using the chair with the control rod 343 fitted into
the opening groove 312, the rotation angle of the back 300 can be
adjusted within the range in which the user manipulates the angle
adjustment lever 330 or within a range limited by the elastic
modulus of the elastic member 340. When moving to a new residence
or delivering the chair, in order to decrease the space occupied by
the chair, after pushing and releasing upwards the control rod 343
from the opening groove 312, by inclining the back 300 forwards
around the connection shafts 320, the back 300 can be folded by
90.degree. or more, such that the angle of the back 300 can be
adjusted to an extent that the upper end of the back 300
substantially approaches the seat 200.
[0101] Hereafter, a chair in accordance with a fourth embodiment of
the present invention will be described.
[0102] FIG. 9 is an exploded perspective view illustrating the main
parts of a chair in accordance with a fourth embodiment of the
present invention, and FIG. 10 is a sectional view illustrating the
main parts in an assembled state.
[0103] In the present embodiment, as in the aforementioned
embodiment, when a user sits on a seat 200, the back of the chair
is moved to be brought into contact with the back of the user. In
this regard, the detailed construction of the present embodiment is
slightly different from that of the aforementioned embodiments.
[0104] The chair according to this fourth embodiment has, as its
main component elements, a base frame 400, a horizontal movement
frame 500, a connection housing 900, elastic members `S`, and
rotation force generation means 700. Specifically, in the present
embodiment, as the base frame 400 is moved upwards and downwards
relative to the connection housing 900, driving force for moving
the horizontal movement frame 500 is generated.
[0105] The base frame 400 is coupled to the lower surface of the
seat 200 such that a space is defined between the base frame 400
and the seat 200. Two hollow pillars 450 are projectedly formed on
the lower surface of the base frame 400. The partial area of the
base frame 400 between the hollow pillars 450 is open. Also, more
preferably, two support brackets 460, needed for installation of
the rotation force generation means 700, which will be described
later, are formed on the base frame 400 and extend downwards while
facing each other. The support brackets 460 are formed on the
opposite edges of the open area which is defined between the hollow
pillars 450 of the base frame 400. The support brackets 460 can be
formed by bending portions of the base frame 400 or by welding
separate plates to the base frame 400.
[0106] The horizontal movement frame 500, which is to be
horizontally moved, is positioned over the base frame 400. The
horizontal movement frame 500 has a shape which has left and right
side walls formed by bending a plate member. Suitable guide means
`G` are provided to allow the horizontal movement frame 500 to be
linearly moved along the base frame 400. Since the structure of
such guide means `G` is well known in the art, a detailed
description thereof will be omitted herein. A follower 510 is
coupled to the lower surface of the horizontal movement frame 500.
As the rotation force generated by the rotation force generation
means 700, which will be described later, is transmitted to the
horizontal movement frame 500 through the follower 510, the
horizontal movement frame 500 can be linearly moved in a horizontal
direction. In the meanwhile, it is preferred that the follower 510
comprise a linearly extending rack gear. A back frame 310 is
connected to the left and right sides of the horizontal movement
frame 500. It is also possible for the back frame 310 to be coupled
to the upper surface of the horizontal movement frame 500 and to
extend across the horizontal movement frame 500 in leftward and
rightward directions. As will be described later, in the case where
a tilting frame 820 is additionally provided on the horizontal
movement frame 500, the back frame 310 must be connected to the
tilting frame 820.
[0107] The connection housing 900 is provided below the base frame
400 in a manner such that the base frame 400 is coupled to the
connection housing 900. As shown in the drawings, the connection
housing 900 is open at the upper end thereof and defines a space
therein. Slide pillars 910 are formed on left and right side walls
of the connection housing 900. The hollow pillars 450 of the base
frame 400 are inserted into respective slide pillars 910, and the
elastic members `S` are disposed between the hollow pillars 450 and
the slide pillars 910. A conventional coil spring can be employed
as the elastic member `S`. When the elastic member `S` is inserted
into the hollow pillar 450, the length of the elastic member `S`
becomes greater than that of the hollow pillar 450, such that the
lower end of the elastic member `S` is brought into contact with
the bottom of the slide pillar 910. The connection housing 900 is
connected to the support 100 in a fixed state, and the base frame
400 can be moved upwards and downwards relative to the connection
housing 900.
[0108] The horizontal movement frame 500 is moved by the rotation
force generation means 700, which is operated in response to the
upward and downward movement of the base frame 400. The rotation
force generation means 700 is installed in the connection housing
900. In further detail, the rotation force generation means 700
includes a meshing portion 711, a meshing body 720, and an
intermediate element 730. The meshing portion 711 is fixedly
installed on the bottom surface of the connection housing 900 and
is brought into contact with the meshing body 720, which will be
described later, to cause rotation of the meshing body 720.
Preferably, the meshing portion 711 comprises a vertically
extending rack gear.
[0109] The meshing body 720 to be meshed with the meshing portion
711 is provided in the connection housing 900. The meshing body 720
is installed on the support brackets 460, which are formed on the
base frame 400 and extend vertically downwards. As shown in the
drawings, holes are defined through the lower ends of the support
brackets 460, and the meshing body 720, fitted around a horizontal
shaft, is inserted through the holes. A bearing is interposed
between the meshing body 720 and the horizontal shaft such that the
meshing body 720 can be rotated around the horizontal shaft. The
meshing body 720 comprises a gear and can be rotated because it is
meshed with the meshing portion 711.
[0110] The rotation force generated in the meshing body 720 is
transmitted through the intermediate element 730 to the follower
510. The intermediate element 730 is connected to the meshing body
720 and is integrally rotated therewith. In the present embodiment,
the intermediate element 730 comprises an arc-shaped gear which can
be directly or indirectly connected with the meshing body 720. The
arc-shaped gear, serving as the intermediate element 730, is meshed
with the follower 510. If the intermediate element 730 is rotated,
the rotation force is transmitted to the follower 510, by which the
horizontal movement frame 500 is linearly moved in the horizontal
direction. The arc-shaped gear, serving as the intermediate element
730, projects through the open area defined in the base frame 400
to mesh with the follower 510.
[0111] Due to this assembly relationship, when a user sits on the
seat 200, the base frame 400 including the seat 200 is lowered with
respect to the fixed connection housing 900. Thereupon, as the
meshing body 720 is rotated on the meshing portion 711, the meshing
body 720 rotates the intermediate element 730. The intermediate
element 730 transmits force to the follower 510 such that the
horizontal movement frame 500 is moved to be brought into tight
contact with the back of the user.
[0112] In constructing the chair having an automatically movable
back in accordance with the fourth embodiment of the present
invention, it is preferable to provide braking means for allowing
the horizontal movement frame 500 to be fixed at a desired position
desired by the user.
[0113] In order to configure the braking means, one side end of the
base frame 400 is bent downwards, and a plurality of engagement
grooves 811 is defined therein. The horizontal movement frame 500
is installed on the upper surface of the base frame 400, and the
tilting frame 820 is additionally installed on the horizontal
movement frame 500. The tilting frame 820 is located in such a way
as to surround the horizontal movement frame 500. An engagement
piece 822, which is to be engaged into the engagement grooves 811,
is formed on and projects from one end of the tilting frame 820.
Further, an adjustment lever 830 is rotatably installed through the
side walls of the horizontal movement frame 500 and the tilting
frame 820, and an eccentric cam 840 is fastened to the adjustment
lever 830. The structure and operation of the adjustment lever 830
is the same as mentioned in the above embodiments. When the
adjustment lever 830 is rotated, as the cam 840 extends through the
horizontal movement frame 500, the cam 840 is brought into contact
with and pushes upwards the tilting frame 820, and according to
this, the engagement piece 822 is engaged into the engagement
groove 811, whereby the movement of the horizontal movement frame
500 is stopped. Therefore, the user can fix the back 300 at a
desired position. If the adjustment lever 830 is rotated further so
that the cam 840 is not brought into contact with the tilting frame
820, the engagement piece 822 is disengaged from the engagement
groove 811, and the horizontal movement frame 500 is converted to a
state in which it can be moved again. In the case where the tilting
frame 820 is provided, the back frame 310 is directly connected to
the tilting frame 820.
[0114] Finally, a fifth embodiment of the present invention will be
described. FIG. 11 is a sectional view illustrating a fifth
embodiment of the present invention.
[0115] In this embodiment, even though a chair is constructed to
have the same construction as the fourth embodiment, when
connecting the connection housing 900 to the support 100, a
connection bracket 1000 is used as an additional element. The
connection bracket 1000 is positioned below the connection housing
900. The connection bracket 1000 is fixed to the support 100, and
the connection housing 900 is rotatably connected to the connection
bracket 1000. An angle adjustment elastic member 1100 is provided
to the connection bracket 1000, and the connection housing 900 is
connected to the angle adjustment elastic member 1100. As shown in
the drawing, the connection housing 900 can be inclined rearwards
with respect to the connection bracket 1000 within a predetermined
range, to improve convenience in a situation such as when a user
takes a rest.
[0116] In the fourth and fifth embodiments, in the same manner as
the other embodiments, the back of the chair can be rotated with
respect to the back frame, so as to be folded.
INDUSTRIAL APPLICABILITY
[0117] As is apparent from the above description, the chair with an
automatically movable back according to the present invention,
constructed as mentioned above, provides advantages in that, since
the back of the chair is always automatically adjusted so as to be
brought into close contact with the back of a user irrespective of
the body condition of the user or despite the poor sitting posture
of the user, the chair can be actually applied to and used in
industry as a conceptually new chair.
[0118] Further, in the present invention, in addition to
convenience in use, because the back of the chair can be
horizontally folded, the space occupied by the chair can be reduced
so as to be easily stored and moved, to thereby increase the
usability of the chair.
[0119] Meanwhile, the chair with an automatically movable back
according to the present invention can be applied to a variety of
articles for sitting, such as chairs for home use and office use, a
vehicle seat, an airplane seat, a sofa, and so forth, which can be
used to seat a person.
* * * * *