Office Chair Central Axis

The office chair central axis typically refers to the supporting and adjusting component located at the center of the chair. Common types include gas springs, mechanical threaded rods, and central load-bearing rods, with their functions and structures varying depending on the chair type.

In swivel chairs, the core component of the central axis is the gas spring (gas lift). This is an elastic element that uses gas and liquid as working media, filled with high-pressure nitrogen gas inside, generating elastic force through different cross-sectional areas of the piston rod. Its core functions include:

1. Support and cushioning: It bears the weight of the human body and absorbs vibrations through gas compression, enhancing seating comfort;
2. Height adjustment: By releasing or locking nitrogen gas through a control valve, it enables seat lifting and lowering to accommodate different heights or desk heights;
3. Angle adjustment (some models): In conjunction with a tilting mechanism, it allows the seat to recline and be fixed at a specific angle;
4. Braking function: It prevents gas leakage through an internal sealing structure, ensuring stability after adjustment. The elastic force of the gas spring can be set by adjusting the nitrogen gas pressure or the piston rod diameter. Its safety must comply with international standards (such as BIFMA certification) to avoid the risk of bursting due to abnormal pressure.

Early computer chairs often used mechanical threaded central axes, consisting of a solid steel rod with threads. The adjustment method involved inverting the chair, loosening the fixing bolt screws, changing the seat height by rotating the steel rod, and then tightening the screws to secure it. This design was simple in structure and low in cost, but manual operation was required for adjustment, and the efficiency was relatively low, gradually being replaced by gas springs.

The central axis of traditional seats such as solid wood chairs may be a central load-bearing rod, usually made of solid wood or metal, directly connecting the seat to the five-star base. Its function is mainly for support, with a fixed height or slight adjustment through mortise-and-tenon joints. It lacks the dynamic adjustment functions of modern swivel chairs but excels in structural stability and durability.

As a core component of office chairs, the design of the central axis must balance mechanical stability and ergonomic requirements. Modern swivel chairs mostly use gas springs for efficient adjustment, while traditional or special-purpose chairs may retain mechanical threaded or solid load-bearing structures. Users can choose the appropriate type based on usage scenarios and budget.