Office Chair Lower Parts
Office chair lower parts mainly include the base, gas lift, five-star base, casters (wheels), and auxiliary parts such as chair foot covers or adjustable feet.
The base is the core adjustment hub of an office chair, playing a crucial role in connecting the seat, gas lift, and five-star base. It integrates mechanical structures internally, enabling functions like seat height adjustment and backrest tilt locking through levers or knobs. Some high-end bases are equipped with synchronous tilt mechanisms that automatically adjust the tilt resistance based on the user's weight, enhancing comfort. The base is typically made of high-strength engineering plastics or metal alloys, requiring sufficient load-bearing capacity and durability.
The gas lift is the core component of a pneumatic height-adjustable chair. It is filled with high-pressure nitrogen (usually at a pressure of 6-8 MPa) and achieves seat height adjustment through piston movement. Its performance directly affects the smoothness and safety of height adjustment: high-quality gas lifts must pass international safety certifications such as BIFMA to prevent sudden seat drops caused by gas leakage or explosion. The height adjustment range of gas lifts is generally 5-10 centimeters, with some models supporting multi-stage locking to meet the needs of users of different heights.
The five-star base, as the structure supporting the user's entire body weight, requires high strength and stability. Common materials include nylon, steel, and aluminum alloy: nylon feet are lightweight and cost-effective but have weaker load-bearing capacity; steel feet offer strong load-bearing capacity but are prone to rust; aluminum alloy feet provide the best overall performance, combining lightweight design with corrosion resistance. The diameter of the five-star base is usually 60-70 centimeters, and the distance between caster mounting holes must match the caster specifications to ensure smooth movement.
The caster material directly affects the mobility experience: nylon casters are the mainstream choice due to their wear resistance, quiet operation, and floor protection; metal casters (such as stainless steel) offer stronger load-bearing capacity but may scratch the floor; polyurethane casters combine the advantages of both and are suitable for hard floors. The diameter of casters is generally 50-75 millimeters, with larger-diameter casters requiring less effort to move but needing to be matched with a wider five-star base.
Auxiliary parts such as chair foot covers or adjustable feet can further optimize the user experience: chair foot covers wrap around the bottom of the five-star base to prevent floor scratches and reduce movement noise; adjustable feet feature a retractable design to balance uneven floors (such as carpet or tile joints), preventing chair wobbling. Although these parts are small, they significantly enhance the practicality and adaptability of office chairs.
