Bottom of Ordinary Office Chair
The bottom of an ordinary office chair typically consists of three main parts: a five-star base, a gas lift, and casters. Some models also include hidden components such as explosion-proof steel plates, adjustment mechanisms, and chassis. Here are the specific structures and functions:
1. Five-Star Base: The Core Structure for Support and Load Distribution
The five-star base is the foundation of the office chair's bottom, usually made of metal (such as steel or aluminum alloy) or reinforced nylon, arranged in a radial pattern with five legs. Universal casters are installed at the ends of these legs, distributing the user's weight evenly to the ground through the star-shaped structure, preventing deformation caused by excessive local pressure. The load-bearing capacity of conventional five-star bases on the market is mostly between 100-150 kilograms, meeting the needs of ordinary office scenarios. Five-star bases made of engineering plastics are lightweight and cost-effective, while metal ones are more durable and suitable for high-frequency use environments.
2. Gas Lift: The Key Component for Height Adjustment
The gas lift is located at the center of the five-star base, connecting the seat to the base through a gas cylinder filled with nitrogen. Users can adjust the height by 10-15 centimeters using a lever control to accommodate different heights or desk heights. Qualified gas lifts must have an SGS-certified explosion-proof steel plate layer, which blocks debris from flying in the event of an accidental explosion, ensuring safety. Regular products must pass 100,000 lift tests to ensure long-term stability.
3. Casters: Designed for Mobility and Floor Protection
Each of the five legs at the bottom is equipped with a universal caster. Modern office chairs often use soft rubber or PU materials to avoid scratching wooden floors or tiles. Casters generally feature a double-ring silent structure, with a metal axle core wrapped in a soft outer layer, reducing sliding noise and minimizing wear caused by carpet friction. Some high-end models also have braking functions to prevent the chair from sliding accidentally on slopes or smooth surfaces.
4. Hidden Components: Supplements for Safety and Function Upgrades
- Explosion-Proof Steel Plate: Some mid-to-high-end models are equipped with an additional steel plate around the gas cylinder to further prevent the gas cylinder from piercing the seat in the event of an explosion, enhancing safety.
- Adjustment Mechanism: A tilt resistance adjustment knob is often installed on the inner side of the support frame, allowing users to adjust the force required for the chair back to recline, accommodating different sitting postures.
- Chassis: As the core adjustment hub, the chassis connects the seat, gas cylinder, and five-star base, usually made of low-carbon steel pipe welding or aluminum alloy die-casting. Its functions include controlling the gas cylinder for height adjustment and enabling the chair back to recline through mechanical structures, although the functions of the chassis in ordinary office chairs are usually relatively basic.
