Abstract: Provided is a cushion structure, which has a cushion base, a bottom support stand, and an adjusting device. The bottom support stand is mounted under the cushion base. The adjusting device is mounted between the cushion base and the bottom support stand. The adjusting device has a back pivot module and a front adjusting module. The back pivot module is connected to the cushion base and the bottom support stand and is mounted on the cushion base and the bottom support stand. The front adjusting module is mounted on a front end of the cushion base and the bottom support stand. The front adjusting module is used to adjust an inclined angle of the cushion base. So the cushion structure can meet needs of different users of different body shapes or with different demands.

Abstract: A bottom plate structure of a chair has a bottom plate, a back rack and a seat frame. The bottom plate has an elastic support device, a slanting device and an adjusting device. The elastic support device has at least one resilient sheet mounted in the bottom plate, an adjusting component mounted in the bottom plate, and a supporting base connected to the adjusting component. The slanting device has a pivoting component connected to the back rack, a transmission seat mounted in the bottom plate, and two fastening members connected to the bottom plate. The pivoting component has two pivoting arms. The transmission seat has a pulling component connected to the transmission seat. The adjusting device is mounted between the bottom plate and the seat frame, and has a back pivoting component and a front adjusting component mounted on the seat frame and the bottom plate.

Abstract: A foldable bracket of a chair contains a positioning rod, a first rotating rod, a connector, a second rotating rod, and a supporting plate. The positioning rod is connected with the chair. The first rotating rod is rotatably coupled with the positioning rod. The connector is joined with the first rotating rod. The second rotating rod is rotatably coupled with the connector, and the supporting plate is connected to the second rotating rod.

Abstract: A foldable leg support contains two rotary arms and a supporting surface between the two rotary arms, and the two rotary arms are rotatably connected with a seat member. When in a rest position, the foldable leg support is pulled outward to expand the supporting surface. Hence, the legs are capable of being extended on the supporting surface comfortably to improve blood circulation, and the foldable leg support is suitable for any size of the legs. When the foldable leg support is not used, the supporting surface is put between the two rotary arms, and, then, the rotary arms and the supporting plane surface are folded under an office chair, saving storage space.

Abstract: A movable chair backrest is substantially composed of an upper board pivotally attached to a front of a backrest frame. A lower end of the upper board is connected to a lower board by a resilient sheet. A bouncing board connects between the lower board and the backrest frame. Therefore, the lower board operationally swings forward, backward, rightward, leftward relative to the upper board to correspond to different sitting and leaning postures of a user.

Abstract: A chair with a resilient back contains a back member, a cushion, and a support member, characterized in that: the support member includes a horizontally hollow tube in which an elastic mechanism is disposed, the back member includes two pressed pieces fixed on two sides thereof respectively, lower ends of the two pressed pieces connect with two ends of the elastic mechanism individually, and the cushion is secured on the support member, wherein the elastic mechanism is a torsion spring, a middle section of the elastic mechanism is fixed, and two outer ends of the torsion spring are coupled with the lower end of the pressed piece.

Abstract: A foldable bracket of a chair contains a positioning rod, a first rotating rod, a connector, a second rotating rod, and a supporting plate, wherein the positioning rod is connected with the chair, the first rotating rod is axially coupled with the positioning rod, the connector is axially joined with the first rotating rod, the second rotating rod is axially with the connector, and the supporting plate is fixed on the second rotating rod.

Abstract: A movable support leg contains a base, a column disposed on the base, a holding surface fixed on the column. The holding surface is fixed and capable of adjusting its height and angle by using first and second rods and the column. A top end of each of the first and the second rods is axially connected with the holding surface by using one screw, and a bottom end of each of the first and the second rods adjusts its height to be fixed on the column.

Abstract: A guiding-wire controlling rod device for chair adjustment is pivotally attached inside a housing by a rotation plate of a pivoting rod. The rotation plate has two sides each with a guiding-wire retaining notch and has multiple abutting flat surfaces formed at a front end of the rotation plate to abut with a resilient sheet to position the rotation plate at different angles. Moreover, a rear end of a controlling rod of the pivoting rod has a pivotal hole to pivotally engage with another controlling rod to drive other guiding-wires. Thereby, the controlling rods are aligned and control respectively multiple guiding-wires for different functions.

Abstract: A multi-section angle adjusting structure for a chair back contains a supporting member axially connected to a base and axially inserted to a sliding groove through a shaft to slide in the sliding groove so that the chair back fixed to the supporting member is adjusted to a desired angle relative to the base. The shaft includes a slidable bar fitted thereon to be connected to a slot of the base. Another end of the slot pushes a toothed block biased against by a first spring which contacts with a stop plate so that the toothed block abuts against an end portion of the slidable bar. The slot includes a positioning structure mounted therein, and the positioning structure includes a toothed seat guided by a guiding line to engage with the toothed block.

Abstract: A foldable leg support contains two rotary arms and a supporting plane between the two rotary arms, and the two rotary arms being axially connected with a seat member, such that when in a rest, the foldable leg support is pull outward to expand the supporting plane, hence the legs are capable of being extended on the supporting plane comfortably to improve blood circulation, and the foldable leg support is suitable for any sizes of the legs; and when the foldable leg support is not used, the supporting plane is put between the two rotary arms, and then the rotary arms and the supporting plane are folded under an office chair, saving a store space.