BACKREST OF THE CHAIR AND ADAPTATION DEVICE FOR THE SAME

• US 20100237679A1
• Filed: 10/28/2008
• Published: 09/23/2010
• Est. Priority Date: 11/02/2007
• Status: Active Grant

• Current Assignee: Okamura Corporation
• Original Assignee: Okamura Corporation
• Inventors: Hara, Eisuke, Tsukiji, Hiroaki
• Granted Patent: US 8,251,454 B2
• Time in Patent Office: Days
• US Class Current: 297/452.180
• CPC Class Codes: A47C 31/023 connecting upholstery to frames, e.g. by hooks, clips, snap fasteners, clamping means or the like
• CPC Class Codes: A47C 7/282 with mesh-like supports, e.g. elastomeric membranes
• CPC Class Codes: A47C 7/40 for the back

Abstract

A backrest of chair in which the lower part of a back frame can be concealed neatly by a stretching material. In the backrest device of a chair where a bag like stretching material (12) knitted or woven in the shape of mesh and opening downward is stretched across a back frame (11) formed by coupling the upper ends of right and left side frames (14a) directing the vertical direction by an upper frame (14b) directing the right and left direction, and coupling the lower ends of both the side frames (14a) by a lower frame (14c) which can be fixed to a backrest supporting rod (8) erected from the upper rear of the seat body of the chair, upper portion of the stretching material (12) is made air permeable, and at least a part at the lower portion of the stretching material (12) covering the lower frame (14c) is made non-translucent.

Claims

1. A backrest of a chair comprising:

a back frame including;

right and left side frames extending in upward/downward directions;

an upper frame extending laterally and linking upper ends of the side frames to each other; and

a lower frame attaching lower ends of the side frames to a backrest support adapter protruding upward from a rear part of a seat body in the chair; and

a baggy stretchable backrest cushion which is inverted to open vertically and is knitted mesh-like or woven,

wherein an upper part of the backrest cushion is air permeable; and

wherein at least a part of the lower backrest cushion covering the lower frame is non-translucent.

2. The backrest of the chair according to claim 1, wherein the density and degree of mesh in an upper part of the backrest cushion is lower and coarser than those in a lower part of the backrest cushion.

3. The backrest of the chair according to claim 2, wherein the side frames are folded in such a manner as to protrude their lower parts forwards;

and that an upper backrest cushion located upper than the folded portions of the side frames has density lower than a lower backrest cushion located lower than the folded portions of the side frames.

4. The backrest of the chair according to claim 1, wherein intermediate portions in the upward/downward direction of both side frames are linked to each other by an intermediate frame curved backwards in an arc shape in planar view, thereby allowing a rear-side backrest cushion to expand backwards.

5. The backrest of the chair according to claim 4, wherein the side frames are folded to protrude their lower parts forwards;

and that intermediate portions of the side frames located upper than the folded portions are linked to each other by the intermediate frame.

6. The backrest of the chair according to claim 5, wherein the upper frames are curved backwards in an arc shape in planar view.

7. The backrest of the chair according to claim 4, wherein an adaptation device for an optional member attachable to a rear side of the backrest is disposed at a central portion of the intermediate frame in the rightward/leftward direction.

8. The backrest of the chair according to claim 1, wherein the back frame includes a back frame body;

and protection members which are attached to both outer surfaces of the side frames in the back frame body and are made of material softer than that of the back frame body.

9. The backrest of the chair according to claim 8, wherein the protection members include inwardly folded portions covering at least outer surface of the connection corners where both side frames meet the upper frame.

10. The backrest of the chair according to claim 8, wherein an elongate groove is formed to extend longitudinally in one of the protection member and the back frame body;

and that an elongate projection is formed in the other of the protection member and the back frame body to complement and to fit to the elongate groove.

11. The backrest of the chair according to claim 8, wherein the back frame body includes the portion for receiving the protection member and indented to the extent of the thickness of the protection member.

12. An adaptation device for adapting a backrest of the chair,

wherein a recess is formed to open rearwards and downwards in the lower frame to be covered with non-translucent part of the backrest cushion according to claim 1;

wherein laterally facing portions in a rear-side lower ends of the recess are linked by a connection bar laterally extending to be integrated with the lower frame;

wherein a connection member is fitted and fixed to the recess in such a manner that a rear-side lower edge of the connection member is abutted to an upper surface of the connection bar;

wherein a plurality of fitting grooves which respectively extends in the upward/downward direction and of which lower end opens downwardly are formed to face to each other in the rear surface of the lower frame within the recess and in the front surface of the connection member; and

wherein a pair of facing fitting grooves receives therebetween an erected portion of the backrest support adapter.

13. The adaptation device for adapting the backrest according to claim 12, wherein in that the pair of facing grooves is formed respectively in the right and left sides to receive the right and left erected portion of the backrest support adapter;

that the facing surfaces of the connection member and the recess receive therebetween a connection plate which links the facing surfaces of the right and left erected portions to each other.

14. The adaptation device for adapting the backrest according to claim 12, wherein a cross section of the facing fitting grooves substantially complement the outer shape of the erected portion of the backrest support adapter.

15. The adaptation device for adapting the backrest according to claim 12, wherein an elastic interlock piece is formed in either the lower frame or the connection member to have a hook protruding from a tip of the interlock piece which elastically engages with an engagement part of the connection plate in case of the lower frame being mounted to the backrest support adapter.

16. The backrest of the chair according to claim 2, wherein intermediate portions in the upward/downward direction of both side frames are linked to each other by an intermediate frame curved backwards in an arc shape in planar view, thereby allowing a rear-side backrest cushion to expand backwards.

17. The backrest of the chair according to claim 3, wherein intermediate portions in the upward/downward direction of both side frames are linked to each other by an intermediate frame curved backwards in an arc shape in planar view, thereby allowing a rear-side backrest cushion to expand backwards.

18. The backrest of the chair according to claim 2, wherein intermediate portions in the upward/downward direction of both side frames are linked to each other by an intermediate frame curved backwards in an arc shape in planar view, thereby allowing a rear-side backrest cushion to expand backwards, and wherein the side frames are folded to protrude their lower parts forwards;

and that intermediate portions of the side frames located upper than the folded portions are linked to each other by the intermediate frame.

19. The backrest of the chair according to claim 3, wherein intermediate portions in the upward/downward direction of both side frames are linked to each other by an intermediate frame curved backwards in an arc shape in planar view, thereby allowing a rear-side backrest cushion to expand backwards, and wherein the side frames are folded to protrude their lower parts forwards;

and that intermediate portions of the side frames located upper than the folded portions are linked to each other by the intermediate frame.