Office chair plastic bases typically employ a one-piece injection molding design. The core consists of a five-star base, connecting plate, reinforcing ribs, and chassis interface, balancing load-bearing stability with lightweight requirements.
The core load-bearing structure supporting the entire chair
Most models feature a five-radial symmetrical layout, with each leg approximately 25-30cm in length. Silent swivel wheels are installed at the outer ends to ensure smooth movement and balanced weight distribution. The mainstream materials are reinforced nylon (PA6+GF) or modified PP, offering high impact resistance and abrasion resistance. Some models have passed a 1500kg static pressure test. TPE cushioning pads are often embedded in the toes to reduce impact damage from hard surfaces against the wheels and also lower pushing noise.
The key hub integrating force and transmission: Located at the center of the five-star base, approximately 18–22cm in diameter, it features standard six- or eight-hole bolt positions for securing the gas spring and chassis assembly. Internally embedded metal inserts (such as zinc alloy nuts) enhance the bonding strength between the plastic and metal parts, preventing stripping over time. The disc surface is often designed with drainage channels and drainage holes to prevent liquid seepage and corrosion of the internal structure.
Reinforcing Rib System: Enhancing overall rigidity and deformation resistance. Radial and annular intersecting ribs are arranged on the back of the base, forming a "hub"-like structure that effectively disperses concentrated pressure from the gas spring. Rib thickness is controlled at 2.8–4.5mm, with a rounded corner at the base to reduce injection stress and the risk of fatigue cracking during long-term use. High-end models employ a honeycomb sandwich structure, increasing flexural modulus without increasing weight.
Chassis Interface and Functional Integration Area: Supports quick-release chassis installation, compatible with the height and reclining adjustment systems of mainstream reclining chairs and ergonomic chairs. Some mid-to-high-end bases have reserved rotation damping adjustment slots, allowing for the connection of external limit devices to achieve "small-amplitude wobbling" or "locked upright" modes. The chassis connecting column height is standardized (commonly 60-75mm), ensuring compatibility with gas springs from different brands.