chair

Abstract

To provide a chair capable of expanding the adjustable range of energization of a spring member by expanding the adjustable range of a vertical position of a contact point between the spring member and a backrest.SOLUTION: A compression coil spring 60 is arranged with its energization directed in a cross direction and comprises a front side engagement part 62 arranged in the front part of the spring and a rear side engagement part 63 arranged in the rear part of the spring. A support body part 41 or a seat 5 of a support base 40 has a front side spring receiving part 55 that is engaged with the front side engagement part 62. The support body part 41 or a backrest 20 comprises a rear side spring receiving part 65 that is engaged with the rear side engagement part 63 and adjustment means for adjusting the position of the rear side engagement part 63 in a vertical direction together with the rear side spring receiving part 65. The upper limit position of the rear side engagement part 63 of the compression coil spring 60 adjusted by the adjustment means is set to be higher than a first shaft center C1.SELECTED DRAWING: Figure 5

Claims

1. Support structure and The support structure is rotatably supported about an axis in the width direction of the chair, and the backrest is displaceable in the front-rear direction between an upright state and a tilted state. A seat having a front supported portion that is supported so as to be movable relative to the front part of the support structure in the front-rear direction, and a rear supported portion that is supported so as to be movable relative to a position above the first axis, and which is displaceable in the front-rear direction in accordance with the displacement of the backrest relative to the support structure, The support structure or the seat and the backrest are provided in a compressed state, and the spring member deforms in accordance with the displacement of the backrest in the front-rear direction, thereby biasing the backrest in a direction that returns it to the upright state. The spring member is arranged with its biasing direction oriented in the front-rear direction and comprises a front engaging portion located at the front of the spring and a rear engaging portion located at the rear of the spring. The support structure or the seat is provided with a front spring receiving portion that engages with the front engaging portion, The backrest comprises a rear spring receiving portion that engages with the rear engaging portion, and an adjustment means for adjusting the position of the rear engaging portion in the vertical direction together with the rear spring receiving portion. A chair in which the upper limit position of the rear engaging portion of the spring member, which is adjusted by the adjustment means, is set to a position above the axis.

2. The upper limit position of the rear engaging portion is set forward and below the rear supported portion. The chair according to claim 1, wherein the distance between the axis and the rear engaging portion at the upper limit position is smaller than the distance between the axis and the rear supported portion.

3. The chair according to claim 1 or 2, wherein the front engaging portion engages with the seat while its upward displacement is restricted.

4. The chair according to any one of claims 1 to 3, wherein the trajectory of the displacement of the front supported portion does not include an upward component.

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