Abstract: A seat support mechanism for a tiltable chair having a rear tilt torque mechanism including interconnected torsion bars which are adjustable to vary the resilient restraining force which opposes rearward tilt of the seat when occupied, a pair of compression springs disposed between a seat support assembly and a base member to provide added resistance to rearward tilt, a link to limit rotation of the seat support assembly within predetermined limits and a release mechanism movable between a lock position, wherein rearward tilt is prohibited and a release position, wherein rearward tilt is permitted.

Abstract: A seat support mechanism for a tiltable chair having a rear tilt torque mechanism including interconnected torsion bars which are adjustable to vary the resilient restraining force which opposes rearward tilt of the seat when occupied, a detent mechanism which provides additional detent and stability to maintain the seat in its normal upright position and add to the resistance of the torque mechanism, and an adjustment mechanism for adjusting said detent mechanism for front tilt.

Abstract: A seat support mechanism for a tilting chair with separate adjustments for front and rear tilt, which mechanism includes interconnected torsion bars which are adjustable to vary the resilient restraining force which opposes rearward tilt of the seat when occupied. The support mechanism also includes a separate torsion member and adjustment to vary the resilient restraining force opposing front tilt of the seat when the seat occupant leans forward.