Abstract: According to embodiments described in the specification, a linear adjustment mechanism for a chair includes first and second structural members adapted to be connected to a chair seat and chair back respectively and coupled to one another for relative sliding movement along an axis. The mechanism further includes a rack on the first structural member extending in a direction of the axis and a pin member positioned in an opening of the second structural member for engaging with the rack. The pin member includes one or more bore openings. One or more spring members are carried by the second structural member for moving the pin member between respective limits of travel of the first and second structural members with respect to one another along the axis. The spring members are disposed through the bore opening for coupling the spring members relative to the pin member.

Abstract: A tilt mechanism for a chair includes rotary stop means defining a plurality of selectable tilted positions of the chair seat/back. In another aspect, an anti kick-back feature is provided based. The mechanism includes upper and lower housing parts and a cushioning spring that normally maintains the parts in a rest position with respect to one another while allowing the mechanism to tilt. A further aspect of the invention provides an improved spring tension control that allows the spring to be installed and removed in a fully relaxed condition so that no special tools are required.

Abstract: A tilt mechanism for an office chair includes a spring tension control that incorporates a wedge arrangement including a moveable wedge component that is displaceable laterally by turning a control knob below the seat of the chair, to force fixed wedge components apart and increase the spring tension. Turning the knob in the opposite direction reduces spring tension.

Abstract: A tilt mechanism for an office chair includes a spring tension control that incorporates a wedge arrangement including a moveable wedge component that is displaceable laterally by turning a control knob below the seat of the chair, to force fixed wedge components apart and increase the spring tension. Turning the knob in the opposite direction reduces spring tension.

Abstract: A mechanism for adjusting the height of a chair back relative to the seat includes an arm that extends upwardly from the rear of the seat, and a carriage that is carried by the back and slidably mounted on the arm. A pinion inside the carriage engages a rack on the arm so that the pinion travels along the rack when the chair back is moved up and down on the arm. A pawl engages the pinion when the chair back is moved upwardly so as to allow incremental adjustment in the height of the back in the upward direction, while preventing downward movement of the back. When the back reaches the upper limit of its travel, an actuator spring is displaced downwardly, disengaging the pawl so that the back is free to slide on the arm. At the bottom of the limit of travel, the spring is displaced upwardly, re-engaging the pawl.