Abstract: A vertically adjustable, multi-position chair arm assembly includes a flat metal support bracket having a generally straight uppermost section. The chair arm assembly further includes a plastic shell housing mounted on the generally straight section of the support tube. The single piece shell housing retains a pair of mating sleeves which seat and lock in the draft angle of the shell housing. The uppermost section of the metal support bracket is enclosed by a molded plastic cover. The mating sleeves provide a channel for receiving and retaining the plastic covered section of the metal support bracket. The sleeve channel provides a plastic to plastic interface whereby the total material tolerances are significantly reduced and thereby minimizing wobble. A locking mechanism housed within the shell housing is in positive locking engagement with a punched locking rack formed in the metal support bracket.

Abstract: A split sleeve bushing for providing a tight fit between a support post and chair base comprises two hemi-cylindrical components which mount about the support post and are received within the support post receptacle of the chair base. The split sleeve bushing includes external stability rings and vertical ribs extending along the external surface thereof. The vertical ribs are tapered to match the draft angle of the support post receptacle of the chair base. The upper end of the split sleeve bushing includes a circumferential flange which is slotted for snap lock engagement with the chair base.

Abstract: A vertically and rotatably adjustable chair arm assembly is secured to a support tube mounted to a chair seat. The chair arm assembly includes a lower outer shell and a plastic sleeve received within an axial bore of the outer shell. A plastic collet is concentrically positioned within the sleeve. The plastic collet includes upstanding positioning tabs adapted for engagement with longitudinally extending alignment grooves formed on the interior surface of the sleeve. The chair arm assembly is secured on the support tube by sliding the sleeve and outer shell slide over the outer surface of the support tube. The plastic collet extends into the upper end of the support tube so that the metal support tube surface is sandwiched between the plastic sleeve and the plastic collet. A lock mechanism having a locking arm telescopically positioned within the plastic collet is pivotally connected to the outer shell.