Adjustable office chair

Seating furniture, in particular an adjustable office chair, with a support structure fixedly attached to a foot stand, a seat carrier and a back rest, wherein at least the inclination of two of the aforementioned parts is variable with respect to each other and may be immobilized in the position desired by means of plates, separated by intermediate shims, and locked by friction, wherein the frictional lock is established with the aid of a clamp bolt and the plates are equipped each with an elongated hole surrounding the clamp bolt, wherein further a relative displacement occurs between the plates and the intermediate shims on the one hand and the clamp bolt on the other, during establishment and release of a clamping position, and wherein further an actuating lever capable of being moved by a spring assembly into a position corresponding to the clamped position, is provided, characterized in that the spring assembly consists of plate springs surrounding the clamp bolt, said spring assembly is supported between a thrust bearing of the clamp bolt on a first side and one of the parts to be adjusted with respect to each other and clamped against each other on a second side, thereby acting through said thrust bearing directly on the clamp bolt and displacing the latter into the clamping position, actuation of the lever moves the clamp bolt, by direct action through said thrust bearing, against the springs, from the clamping position into the release position.