A seat assembly (21) including a seat (22), a backrest (23) and a mounting assembly (24) mounting the seat (22) in a near horizontal orientation for movement along an upwardly concaved arcuate seat path having a center of curvature (37) proximate the center of mass (39) of a person seated on the seat, and the mounting assembly (24) further mounting the backrest (23) in a near vertical orientation for movement independently of the seat along a forwardly concaved arcuate path having a center curvature (37) proximate the center of mass (39) of the person. An adjustment assembly (61) is provided for adjusting the radius of curvature of the path of motion of the backrest (23). Also provided are a backrest tilt adjustment assembly (71), an armrest adjustment assembly (90), a seat biasing assembly (110) and a seat motion latching assembly (111). A method of self-adjusting support and alignment of a backrest also is disclosed.
The invention relates to a chair, especially an office or work chair or similar, whereon a back-rest part (15) can be placed in an inclined position from an initial or rest position via a first axis of rotation (12). A seating part (14) performs a longitudinal displacement around a second axis of rotation (20) and an inclined displacement around a third axis of rotation (11) in a synchronous manner with respect to the inclined movement of the back-rest part (15). A return device (13) is provided for returning the back-rest part (15) and/or seating part (14) to the initial position or rest position. The office chair (1) comprises a carrier frame (5) which disposed centrically on the leg frame (2) and which supports in a stationary manner the first axis of rotation (12) on the centre of the leg frame, said axis of rotation remaining at a constant, predetermined distance above the seating part (14) in the rest position and in all inclined positions of the back-rest part (15). Said first axis of rotation (12) is connected in a secure manner to the back-rest part (15) by means of a pivoting lever (16).
An adjustable motion wheel chair having a mobility base for supporting a back panel and a seat panel. A pair of control plates are mounted to the mobility base and positioned laterally across the mobility base in spaced apart parallel relation. The back panel includes a pair of pivot pins located on opposite lateral edges of the back panel which are pivotally received by a respective control plate. A linkage member hingedly connects the seat panel to the back panel. Each control plate includes a forwardly extending stop for limiting the downward movement of a front edge of the seat panel. A latch member is attached to each control plate and is operable between a first position where the back panel is fixed in angular relation with the seat panel and a second position where the back panel is rotatable with respect to the seat panel.
