Abstract: Provided is a chair in which the rear section of the seat can be raised with good lateral balance, in which the seat is stable, and that has a simple structure and a good appearance. The disclosed chair includes a seat (6) that is pivotally attached by means of a laterally-oriented pivot shaft (9) to a support base (5) supported by (a) leg(s), the rear section of the seat (6) being pivotable in the vertical direction. In said chair, an urging means (12) that urges the seat (6) upward is constructed so as to include: an elastic expanding-and-contracting component (13) that connects a portion of the support base (5) located below the pivot shaft (9) and a portion of the seat (6) located to the rear of the pivot shaft (9); and a pair of leaf-spring-like elastic warping components (14) provided on the right and left sides of the elastic expanding-and-contracting component (13).

Abstract: A backrest device for a chair, capable of, without a reduction in its strength and rigidity, effectively bending backward so as to follow the shape of the back of a person seated on the chair, providing the person with excellent sitting comfort. In the backrest device, a back board is supported by a backrest frame, and the back board has a flexible back stopper on the inner side of a back frame. The thickness of a vertical intermediate section of the back stopper is gradually increased from both left and right sections of the intermediate section toward the center such that the thickness is less in both left and right sections and is maximum at the center.

Abstract: A headrest device of a chair in which a headrest can be stably supported by a headrest frame and the operation for mounting a vertically moving member of the headrest is easily performed. Guide grooves are formed in the side faces of guide rails at the front faces of the right and left side-rods of the headrest frame. The right and left guide rails are so held by a pair of right and left lifting brackets, which are provided on the rear surface of the headrest and are formed in rearward U-shape when viewed from above, as to be capable of sliding vertically from the front. Projected guide pieces formed to be projected on the inner surfaces of both vertically moving brackets and facing in the vertical direction are slidably fitted into the guide grooves of the right and left guide rails.

Abstract: A flexible base board for a chair, easily bends into a desirable shape. The base board fits more appropriately to the body of the person seated on the chair following the shape of the person's body without pressing the back, etc., thereby providing the person with good sitting comfort. The flexible base board is used for the backrest, etc. of a chair. The base board has an upper shell (4), an intermediate shell (5), and a lower shell (6). A large number of holes (14) having substantially the same size are substantially uniformly formed in the entire shell (6). Also, a large number of holes (15) are formed in the entire surface of the intermediate shell (5), and each hole (15) has a greater transverse width than a hole (14) in the upper shell (4) and the lower shell (6).

Abstract: A backrest device for a chair, capable of, without a reduction in its strength and rigidity, effectively bending backward so as to follow the shape of the back of a person seated on the chair, providing the person with excellent sitting comfort. In the backrest device, a back board is supported by a backrest frame, and the back board has a flexible back stopper on the inner side of a back frame. The thickness of a vertical intermediate section of the back stopper is gradually increased from both left and right sections of the intermediate section toward the center such that the thickness is less in both left and right sections and is maximum at the center.

Abstract: A flexible base board for a chair, easily bends into a desirable shape. The base board fits more appropriately to the body of the person seated on the chair following the shape of the person's body without pressing the back, etc., thereby providing the person with good sitting comfort. The flexible base board is used for the backrest, etc. of a chair. The base board has an upper shell (4), an intermediate shell (5), and a lower shell (6). A large number of holes (14) having substantially the same size are substantially uniformly formed in the entire shell (6). Also, a large number of holes (15) are formed in the entire surface of the intermediate shell (5), and each hole (15) has a greater transverse width than a hole (14) in the upper shell (4) and the lower shell (6).

Abstract: A chair in which a backrest can be largely tilted rearward within a small rotation angle range without increasing the heights of a leg body and a seat body. The leg body (1) includes a pair of left and right side-legs (9) of angular shape in side view, each having a front leg (9a) tilting forward and downward and a rear leg (9b) tilting backward and downward. The lower end of a backrest support frame (3) is so pivotally mounted on the leg body (1) at an appropriate position under the seat body (2) as to be capable of tilting rearward between the left and right side-legs (9).

Abstract: A headrest device of a chair in which a headrest can be stably supported by a headrest frame and the operation for mounting a vertically moving member of the headrest is easily performed. Guide grooves are formed in the side faces of guide rails at the front faces of the right and left side-rods of the headrest frame. The right and left guide rails are so held by a pair of right and left lifting brackets, which are provided on the rear surface of the headrest and are formed in rearward U-shape when viewed from above, as to be capable of sliding vertically from the front. Projected guide pieces formed to be projected on the inner surfaces of both vertically moving brackets and facing in the vertical direction are slidably fitted into the guide grooves of the right and left guide rails.