Abstract: The invention relates to seat device, in particular an office chair, with a seat element, a backrest, a support frame on which the seat element and the backrest are disposed with a plurality of joints and sensors disposed on the seat device. The sensors detect physical and/or chemical properties generated by the seat device.

Abstract: To provide for a compact seat adjustment mechanism, an elongated seat support (21) is secured to a floor support structure including a central post (13), to extend at an upwardly directed angle of inclination. The seat (17), attached to a seat support (29), is pivotally located to pivot about an axis (37) close to the front edge of the seat. The seat is maintained in position by a torsion spring assembly (23), the spring tension of which is adjustable by a laterally positionable adjustment knob (63), and a blocking element in form of a gas spring or hydraulic spring (27) couples the seat to the seat support, the respective blocking element being attached with a first end between the pivot axis support and the floor support and with its other end to the seat (17) such that it will extend in the genral direction of the elongated seat support (21) and form an acute angle with respect to the seat support, which angle will be somewhat greater than the angle of inclination of the seat support (210 itself.