Abstract: A resilient leaning position-restoring device for a height-adjustable chair back of an office chair includes a back support unit, a height-adjustable chair back disposed on the back support unit, and a resilient leaning position-restoring device disposed between the back support unit and the chair back. The resilient leaning position-restoring device essentially includes a sliding element slidable along a slot disposed on the back support unit and being pulled downward by a spring. The upper end of the sliding element extends to form a resilient member of an inverted U shape. A lower end of the resilient member is coupled to the chair back. The resilient member maintains the predetermined resilience thereof for supporting the bottom of the chair back while height adjustment of the chair back is underway. The bottom of the chair back lends proper support to the sitter's waist, regardless of an adjusted position of the chair back.

Abstract: A chair leg rest assembly includes a supporting arm pivotally coupled to a chair seat, and a leg rest frame that can slide along and be selectively positioned on the supporting arm for providing a support plane. An upper end of the supporting arm is flanked by two pivot holders that are fixed to the seat. One of the pivot holders has a pawl portion to be engaged with a pawl portion of a pawl core that is received in the upper end of the supporting arm and resiliently pushed outward. As the supporting arm pivots against and is positioned with respect to the pivot holders, the leg rest frame can be retracted under or expanded before the seat. Then the leg rest frame can slide outward and to support a user's stretched legs on the support plane thereof. The leg rest assembly is thereby easy to operate.

Abstract: An ergonomic headrest for an office chair is provided. The headrest includes a pillowing member. The pillowing member includes a moderately bulging upper pillowing side and a substantially convex cervical pillowing side and has a slightly depressed occipital pillowing side formed therebetween. A resilient element is disposed behind the headrest for abutting against the headrest resiliently. With the sitter's head resting on the headrest, the sitter's neck and occiput rest on the cervical pillowing side and the occipital pillowing side exactly. Hence, the sitter's neck and occiput can rest on the ergonomic headrest which contours thereto. This, coupled with the resilience and ergonomic contour of the headrest, enables the sitter's head to receive ergonomic and comfortable support.

Abstract: A resilient leaning position-restoring device for a height-adjustable chair back of an office chair includes a back support unit, a height-adjustable chair back disposed on the back support unit, and a resilient leaning position-restoring device disposed between the back support unit and the chair back. The resilient leaning position-restoring device essentially includes a sliding element slidable along a slot disposed on the back support unit and being pulled downward by a spring. The upper end of the sliding element extends to form a resilient member of an inverted U shape. A lower end of the resilient member is coupled to the chair back. The resilient member maintains the predetermined resilience thereof for supporting the bottom of the chair back while height adjustment of the chair back is underway. The bottom of the chair back lends proper support to the sitter's waist, regardless of an adjusted position of the chair back.

Abstract: An adjustment structure of a chair armrest is provided. The armrest is attached to a chair back through a fastening seat. A releasable fastener provided between the armrest and the fastening seat allows the armrest to be slide vertically and get positioned with respect to the fastening seat. The fastening seat has a guiding groove facing the armrest and the guiding groove is formed with toothed portions. The releasable fastener includes an engaging member for bilaterally engaging with the toothed portions, mutually engageable slanting tooth portions formed on a lever and a driven member assembled to the armrest, respectively, and a screw passing through the engaging member and the guiding groove to be screwingly fixed to the driven member. By pulling the lever upward or downward, the armrest is released to be repositioned or is positioned so that the armrest attached to the chair back can be adjusted in altitude.

Abstract: A resilient lower-back supporting device capable of vertical adjustment along with a backrest of a chair includes a resilient supporting unit pivotally connected between a lower end of the height-adjustable backrest and a supporting element. Configured for resilient extension and retraction, the resilient supporting unit includes an outer supporting rod and an inner supporting rod inserted therein. The two supporting rods are pulled toward each other by a spring provided therebetween. Besides, a spring is provided at an outer end of each supporting rod to bias the resilient supporting unit and the backrest toward a predetermined direction. With the backrest being vertically adjustable, and with the resilient support provided by a lower-back supporting portion at the lower end of the backrest, people of different heights are ergonomically supported especially on the lower back while sitting in the chair and are protected from back pain attributable to a prolonged sitting posture.

Abstract: A resilient lower-back supporting device capable of vertical adjustment along with a backrest of a chair includes a resilient supporting unit pivotally connected between a lower end of the height-adjustable backrest and a supporting element. Configured for resilient extension and retraction, the resilient supporting unit includes an outer supporting rod and an inner supporting rod inserted therein. The two supporting rods are pulled toward each other by a spring provided therebetween. Besides, a spring is provided at an outer end of each supporting rod to bias the resilient supporting unit and the backrest toward a predetermined direction. With the backrest being vertically adjustable, and with the resilient support provided by a lower-back supporting portion at the lower end of the backrest, people of different heights are ergonomically supported especially on the lower back while sitting in the chair and are protected from back pain attributable to a prolonged sitting posture.

Abstract: A reversing assembly for an office chair armrest is provided. Therein, an armrest is provided atop with a positioning element, so that the armrest, by combination of a fastening element and the positioning element, is pivotally positioned between the fastening element and the positioning element. The armrest is provided with a ball to be resiliently laid into one of positioning holes formed on the positioning element. Thereby, the armrest, when posed forward, is allowed to swing in both directions in a predetermined range, and the armrest is also allowed to rotate 180 degrees so that the reversed armrest is absent to touch the desk-top, and thereby the seat and legs of the chair can be received under the desk-top.