Abstract: An adjusting mechanism is provided for selectively positioning a chair component such as an armrest or a backrest. The adjusting mechanism utilizes a first member having a longitudinal axis. A plurality of ratchet recesses are spaced longitudinally along the first member. A second member having a longitudinal axis is disposed in substantially parallel relation with the longitudinal axis of the first member. The second member supports a ratchet dog. The first and second members are relatively movable along their longitudinal axes between a ratchet dog-blocking position and a ratchet dog-releasing position. A spring is mounted on the second member for urging the ratchet dog into successive engagement with the plurality of ratchet recesses. A slider is movably mounted on the second member for selectively displacing the spring to effect disengagement of the ratchet dog from the successive ratchet recesses.