CHAIR

• US 20090146476A1
• Filed: 08/18/2006
• Published: 06/11/2009
• Est. Priority Date: 08/18/2005
• Status: Active Grant

• Current Assignee: Itoki Corporation
• Original Assignee: Itoki Corporation
• Inventors: Nakamura, Yasuhiro, Kan, Satoshi, Sakurai, Tamio, Hama, Katunori
• Granted Patent: US 7,794,017 B2
• Time in Patent Office: Days
• US Class Current: 297/284.400
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03272 with coil springs
• CPC Class Codes: A47C 1/03274 of torsion type
• CPC Class Codes: A47C 1/03294 slidingly movable in the base frame, e.g. by rollers
• CPC Class Codes: A47C 7/46 with special, e.g. adjustable , lumbar region support profile; "Ackerblom" profile chairs

Abstract

A front portion of a seat 2 is connected to a base 6 by a front support link 7 and a first support shaft 8, and a rear portion of the seat 2 is connected to a rocking frame 11 by way of a rear support link 14. The first support shaft 8 is slidably fitted to the base 6. An upper portion of the backrest 3 is attached to an upper portion of a back frame 12. When a person is seated, the seat 2 is moved down and moved back, and a lumber support portion 17a of the backrest 3 is moved forwardly in cooperation with movement of the seat 2. Therefore, even when a person is shallowly seated on a chair, the waist portion of the person can precisely be supported. The cooperatively moving means includes a cooperatively moving link mechanism comprising a first through a fifth cooperatively moving link 43, 46, 48, 21 and 20. The third link 48 can be pivoted to return against an elasticity of a second returning spring 49. Therefore, a person is not hampered from being seated thereon deeply.

Claims

1. A chair comprising:

a seat;

a seat receiving member supporting the seat, the seat receiving member being configured to move the seat at least one of downward and rearward in response to a person being seated on the seat;

a backrest including a lumbar support portion that supports the lumbar of the seated person at a lower portion of the backrest; and

a cooperative moving unit configured to forwardly move the lumbar support portion of the backrest in response to at least one of the downward and rearward movement of the seat.

2. The chair according to claim 1, wherein the seat receiving member moves the seat downward without changing an attitude of the seat in a side view of the seat when the person is seated;

and

the lumbar support portion of the backrest is moved forward in response to at least one of the downward and rearward movement of the seat.

3. The chair according to claim 1, further comprising:

a base provided at an upper end of a leg stay;

a back support frame rearwardly inclinably connected to the base; and

a rocking spring that elastically supports a rearward inclining movement of the back support frame;

wherein the seat is supported by the base and the back support frame such that the seat moves downward and the back support frame rearwardly inclines without changing an attitude of the seat as viewed from a side of the seat when the person is seated;

and

a spring force of the rocking spring is set such that the rocking spring is not elastically deformed when the person is seated but not leaning on the backrest, and is elastically deformed when the person is seated and is leaning on the backrest.

4. The chair according to claim 1, further comprising:

a base provided at an upper end of a leg stay;

a back support frame rearwardly inclinably connected to the base; and

a rocking spring that elastically supports a rearward inclining movement of the back support frame;

wherein the seat is connected to the base and the back support frame such that the seat moves downward and rearward without changing an attitude of the seat in a side view of the seat when the person is seated by way of the seat receiving member being provided with a first link mechanism;

the seat is biased in an upward direction by the spring; and

the back support frame is provided with a second link mechanism that converts the rearward movement and the downward movement of the seat into the forward movement of the lumbar support portion of the backrest, the second link mechanism being included in the cooperative moving unit.

5. The chair according to claim 1, wherein the cooperative moving unit includes means for converting the movement of the seat into the forward movement of the lumbar support portion of the backrest;

and

the forwardly moved lumbar support portion is permitted to move back against the means for converting the movement.

6. The chair according to claim 1, wherein the backrest is flexible to deform in a side view and a plane view by being pressed by the seated person;

an upper portion of the back rest being connected to a back supporter, the lumbar support portion being connected to the cooperative moving unit; and

the lumbar support portion is moved forwardly and rearwardly by inclining the backrest centering on the upper portion of the back rest in a side view thereof.

7. The chair according to claim 6, wherein the backrest includes a back plate formed of a synthetic resin including an elastomer, and a plurality of vertically prolonged ribs are formed at one of a front face, a rear face, and both the front and the rear face of the back plate.

8. The chair according to claim 1, wherein the backrest includes a flexible lumbar support portion deformable in a side view direction thereof, and a rigid main support portion disposed upward from the flexible lumbar support portion;

wherein the main support portion of the backrest is attached to a back support frame;

an upper end of the lumbar support portion is connected to an upper support portion or the back support frame and a lower end thereof is movably held;

the lumbar support portion is deformed in a direction such that a lower portion of the lumbar support portion is moved upwardly by a stretching operation from a lower side;

the lumbar support portion is deformed in a projected shape and moved forwardly in a side view thereof; and

the back support frame is provided with a guide unit for moving the lower portion of the lumbar support portion upwardly when the person is seated and the guide unit is included in the cooperative moving unit.

9. The chair according to claim 8, further including:

a base provided at an upper end of a leg stay;

the back support frame rearwardly inclinably connected to the base; and

a rocking spring that elastically supports a rearward inclining movement of the back support frame;

wherein the seat is supported by the base and the back support frame by the guide unit such that the seat moves rearward and downward without changing an attitude of the seat in a side view of the seat when the person is seated;

and

a downward directed extended portion having a flexibility is continuous to a lower portion of the lumbar support portion, a front end thereof is connected to a rear portion of the seat,

the back support frame is provided with a guide portion by which the seat is moved down and moved back; and

the downward directed extended portion of the lumbar support portion is moved to the main support portion of the back rest.

10. The chair according to claim 5, wherein the means for converting the movement comprises a spring.

11. A chair comprising:

a seat;

a backrest including a lumbar support; and

a device operatively connecting the backrest to the seat, the device configured to convert at least one of downward and rearward movement of the seat into forward movement of the lumbar support.

12. The chair according to claim 11, wherein a sum of the rearward movement of the seat and the forward movement of the lumbar support is between 50 mm and 100 mm.

13. The chair according to claim 11, further comprising:

a base provided at an upper end of a leg stay; and

a back support frame connected to the base;

wherein the seat is supported by the base and the back support frame.

14. The chair according to claim 13, wherein the device comprises a plurality of cooperative moving links.

15. The chair according to claim 14, wherein the plurality of cooperative moving links comprises five cooperative moving links.

16. A chair comprising:

a seat;

a backrest including lumbar supporting means; and

means for converting downward and rearward movement of the seat into forward movement of the lumbar supporting means, the means for converting movement operatively connecting the backrest to the seat.

17. A method of adjusting a chair, the chair including a seat and a backrest having a lumbar support, the method comprising:

converting at least one of downward and rearward movement of the seat into forward movement of the lumbar support.